Email marketers love email marketing terminology.

There’s nothing wrong with that – but for people new in the game, it’s a source of constant confusion and consternation.

But fear not, dear email marketers! Phrasee’s got your back.

Welcome to the Awesome Glossary of Email Marketing Terms.

In this glossary, you’ll find a bunch of commonly used phrases in the email marketing world. Wonder no more what they mean – find all your answers here!

Abandoned cart email

When someone comes to your site, puts items in their basket… and then doesn’t end up buying it, that’s annoying, right?

Abandoned basket emails help solve this problem. It’s a triggered email that is sent to said customer, enticing them to come back and complete their purchase.

When done in a non-creepy way, it can be a boon to your bottom-line. When done in a creepy way, it’s an express train to a restraining order.

ALT Text

Adding an image of a fainting cat to your hilarious newsletter? Don’t forget the Alt text. Alt text is a word or phrase that describes the content and/or function of an image. It’s added as an attribute to an HTML file, inside an image tag and after the character sequence ‘alt =’.  If for any reason the image does not load, or the user has chosen not to display images, the ALT text is displayed in its place. But that’s not all the ALT text can do:

  • It can be read by screen readers, so visually impaired users can access descriptions of any images used.
  • In cases where images don’t load due default blocking by an email client, bad connectivity, or broken links, the ALT text prevents any context being lost.
  • ALT text can aid in SEO by providing a semantic context to images that is readable by search engines, so that that person searching for “funny cat photos” can come across that same fainting cat image in a search engine and be steered to your commercial website, where they belong.  

Average revenue per email sent (ARPES)

Wondering how to measure the overall efficiency of your email marketing efforts? ARPES (average revenue per email sent) is a great place to start. ARPES is calculated by dividing the sum total of revenue generated by an email marketing campaign by the total number of emails sent over the course of that campaign.

It is useful to determine the overall performance of specific email marketing campaigns, which is good, because if you can’t prove that your emails actually generate revenue you will end up penniless and homeless and no one will ever love you.

More info:

Average revenue per user (ARPU)

A close cousin of ARPES (average revenue per email sent), ARPU is a metric aimed squarely at a mailing list’s subscribers and how they respond to a company’s overarching email marketing strategy. It is calculated by dividing the sum total of revenue generated by an email marketing campaign by the total number of subscribers on the mailing list for that campaign.

This stat is useful in determining how well an audience of subscribers is being reached by a company’s campaigns overall, which is important, since if your emails are not holding the attention of your subscribers your overall approach is definitely lacking. And that wouldn’t make your mum very proud, would it?


Email automation refers to email campaigns that automatically send when a person does something that is set to trigger these automated emails.

For example, if a subscriber buys a pair of leopard print bikini briefs from your retail site, an automated campaign could immediately send them a follow-up email which reads: “Congratulations on your new bikini briefs! Perhaps you would be interested in this matching selfie stick to show the world how much you love them?”

This approach saves the time and money because it means you don’t need to manually create and send an email every time someone performs a frequent activity such as signing up to your newsletter or buying something from your site.

Of course, if your company prefers wasting time and money sending such emails manually is always an option.


Blacklist is a DNS tool that prevents those pesky spam emails reaching unsuspecting people’s inboxes. And yes, winding up on one is every bit as terrible as it sounds. It involves a real-time database of IP addresses that have been identified as locations where spam emails are sent. Emails sent from these addresses are immediately identified as spam, although the final decision whether or not to filter these messages lies with the user’s ISP.

If your emails and their attendant subject lines are boring and unimaginative, your odds of ending up on one or more of these black lists increases exponentially.

Body Content

The body is the main part of any email. It encompasses the copy, images and any attachments of the email (although some of these may be displayed elsewhere). 

An email with a stunning subject line and a poorly crafted body will generally fail to produce positive results beyond the initial open, like most recent seasons of “The Walking Dead”, or Green Day’s last 3 albums.


For an email marketer, a “bounce” is not nearly as much fun as it sounds. It occurs when a sent email cannot be delivered to the designated email address for some reason…  Typically, the sender will receive an email explaining exactly why the email could not be delivered, but this rarely makes us feel any better about what has just happened.

More info:

Bounce (hard)

In email marketing, the hard ounce feels like the ultimate betrayal. It occurs when a sent email is permanently undeliverable due to an invalid email address because the account is either no longer active, or was a fake address given to us as a decoy. And they never even let us know… How rude!

More info:

Bounce (soft)

The soft bounce is the most gentle of all the bounces. It occurs when a sent email is recognised by the recipient’s server, but cannot be delivered because of a temporary issue, such as a full inbox or an out-of-office notice. This indicates that the email address used is still valid, but temporarily unavailable.

Email marketers can take solace in the fact that such recipients still want to hear what they have to say, they just don’t have time or space to listen right now.

More info:

Calls-to-action (CTA)

An instruction (usually written in the imperative) urging the reader of an email to take immediate action. Examples include: click here, call now and signup now.

The function of the call to action is predicated on the supposition that people will do what they are told, whether it improves their lives or not, like the “open here” arrow on a box of hot dogs.


A statistic that indicates that your email recipient has clicked on a link included in the body of your email.

Want to get an extra click or 2 in your next campaign? Three words: Cat video link.

Click rate or click-through rate (CTR)

Need to determine whether or not your marketing emails are getting your mailing list to where you want them to be? Check out your click rate! Click rate measures the percentage of emails sent in a particular email marketing campaign which resulted in the recipient “clicking” on one or more of the links offered in the marketing email.

E.g. if a marketing email is sent to 10 recipients, 4 of whom both open the email and click on one or more of the links contained in the email, the click rate of that campaign would be 40%. This metric can give a general indication of the overall effectiveness of an email marketing campaign, in terms of generating recipient interest.

Pro-tip: Try adding a “click here for free chocolate” link on your next campaign and watch this metric soar

More info:

Click to open rate (CTOR)

Need to determine how your emails are performing in driving traffic once they are opened? Well click to open rate might be just what you need. This metric measures the percentage of clicks on links included in an email campaign against the number of opened emails in that campaign. This metric differs from click rate in that, rather than measuring total clicks against all emails sent, it focuses on the click rate only for those sent emails that were opened by the recipient. This metric can indicate the effectiveness of the design, layout, ease of use, and copy of the marketing email body itself, rather than the campaign as a whole.

And remember, it’s not your fault. Anyone who opens an email and doesn’t click on the attached links is a jerk.

More info:


The high point of any email marketer’s life is the conversion. This metric represents the total number of wonderful folks who performed the desired action or outcome that the email marketer originally hoped to achieve when crafting and sending a marketing email. For example, this could be for the recipient to click a link in the email and make a purchase, to download a report, join a mailing list, or sign-up to an event.

If the email’s recipient performs this action when they receive your email then they cease to be a human being with hopes, dreams and feelings, and are now considered simply a “conversion”.

Conversion rate

Conversion rate is a metric for measuring the percentage of emails that resulted in the recipients taking the action set as the goal of the marketing email. In other words, how many emails resulted in recipients subscribing, donating, or making a purchase when measured against the total number of emails sent.

If an email marketer’s emails produce a high conversion rate, they can be considered a success. If they produce a low conversion rate, the email marketer is a failure, and should be mocked and harassed relentlessly until they either raise their conversion rates or quit the field in disgrace.

More info:

Cascading style sheets (CSS)

Also known as “the coder’s dream”, a cascading style sheet (or CSS) is a stylesheet language that’s used to describe the visual style of elements written in a markup language such as HTML. And if that sentence makes no sense to you, you probably don’t actually need to know what cascading style sheets are. Please move along.

There are three methods of applying CSS to HTML: External style sheets, embedded or inline styles. However, external and embedded styles are often stripped or blocked from the email by email clients. As inline style sheets are added to the HTML document on a tag by tag basis they are the least likely to be altered or blocked in email, so are the most appropriate for CSS use in email.

For those who did not follow the preceding sentence: why are you still reading? We already told you. Move along.


Are your emails getting to the inboxes you want them to reach? They damn well better be. Deliverability is the metric used to measure an email sender’s ability to get his/her marketing emails to arrive in their recipients’ inboxes, rather than being relegated to the spam folder or being sent to inactive email accounts.

High deliverability rates are generally associated with successful email marketing campaigns as recipients are much more likely to lay eyes on marketing emails in their inbox. Low deliverability rates are generally associated with crappy subject lines, out of date mailing lists, or blacklisted senders. Recipients of such emails will probably never lay eyes on your marketing emails and thus the entire exercise becomes a complete waste of time and effort, since nobody ever looks in their spam folders.

DomainKeys Identified Mail (DKIM)

A form of email authentication in which a sender identifies valid messages sent from their domain by affixing a digital signature to them. In this way, an email sender can protect their domain from spammers who wish to forge spam emails and disguise them as having been sent by that domain. All emails sent from a domain can be filtered by a domain name service (DNS) to check for this digital signature and separate the forged spam messages from the authenticated ones.

It’s like having a bouncer at your bar who doesn’t simply accept “I’m with the band” as a valid explanation for why everyone should be let in for free.

Mmmmm… Spam…

Email client

Possibly the most nonsensical and confusing of email marketing’s many terms, an email client is a computer program that allows users to send, receive, read, and organise their emails. The email client provides and manages the direct interface between the user and his/her emails. It is called a “client” because email systems are based on a client-server architecture, meaning that all computers being served by a particular server are considered to be that server’s “clients”. But it’s still really weird, if you think about it.

Email service provider (ESP)

ESP is the ability to intuitively sense things which regular people can’t… Just kidding! There’s no such thing as that. ESPs are actually software companies that facilitate the transmission of email marketing. The core functions of ESPs include storing of customer data, uploading of HTML email content, and ultimately the lauded “launch” button which sends your emails to the masses. There are hundreds of ESPs in the marketplace, although a small number of market leaders dominate.

More info:

From name (sender name)

Wondering who sent you that email wishing you a happy birthday? Well you might want to look at the from name for that email. The “from name” is the name which appears in the from section at the beginning of any email (as it appears in the inbox). It indicates precisely who the original sender of an email was. In email marketing the from name is typically the name of the company which is marketing itself.

Companies which have built and maintained a positive brand image in past interactions will be much more likely to result in an open. Those which have not built and maintained a positive brand image will generally find their emails ignored, sent to the spam box, and viewed with disdain/disgust by all who receive them.


Interested in knowing what an email is about without having to waste valuable energy rolling your eyeballs downward and side to side? Well feast your weary eyes on the mighty header. Headers are the lines of text preceding (above) the body copy of an email, which provide the message’s routing information. This information typically includes the sender/from name and recipient name, as well as the date the email was sent and the subject line (the most important part of any email).

Hyper text markup language (HTML)

HTML is the standard markup language used to describe the content and structure of web pages, emails and applications. It is a cornerstone internet technology, and without it the world would be plunged into eternal darkness and chaos.

IP address

An IP address is the unique code assigned to each computer (or other internet using device) in a network. It states both the identity of the device and its location.

The government uses every IP address to track all the people of the earth and probably trades the information to aliens in exchange for ray guns and spaceships so we can be more easily rounded up and ground into alien baby food.

Lotus Notes (now ``IBM Notes``)

Developed in 1989 by the Lotus Development Corporation, Lotus Notes is a legend in email marketing circles for being the worst email client ever. It appears to have been specifically designed to make the lives of email marketers resemble hell on earth as closely as possible.

Multipurpose internet email extensions (MIME)

MIME is a type of email message construction in which it is possible to include non-text elements (such as images, audio or video, multiple part message bodies), and alternative character sets (such as emojis). MIME is the basic template which makes up the structure for modern emails.

If it wasn’t for MIME we would all still have to converse in emails without the aid of gifs, memes, and emojis, which would be terrible, since we might realise that we actually have nothing to say to one another.

MX Record

An MX record is a resource record (possibly overseen by the Illuminati) in a DNS that states which mail server has responsibility over mail delivery, and the priority sequence of all host names within the same domain.

When there is more than one mail server a preference number is assigned to each; the lower the preference number, the higher that server is in the order of delivery priority. Toe the line and THEY might not move you to the bottom of the list.


An open is a statistic that indicates your email has been opened by the email recipient

Sadly, every time a marketing email goes unopened, a fairy loses her wings.

Open rate

The open rate is the measurement of the percentage of emails, sent in a particular email marketing campaign, that were opened by the people who received them. E.g. if a marketing email is sent to 10 recipients, 2 of whom open them, the open rate of that campaign would be 20%. This metric can indicate the effectiveness of the email subject lines used, and can also reflect recipient perceptions of the sender’s brand.

A high open rate should always directly result in a well-paid email marketer. Sadly, this is sometimes not the case.

Opt-in (single)

In a perfect world, an opt-in would occur only when a user decides to subscribe to a company’s email list by voluntarily submitting their email address with a clear understanding of what they are agreeing to.

Here in the real world, however, an opt-in can occur when someone gives their email address to the cashier at a clothing store, when they forget to click on the automatically generated check mark on an opt in box on a website, or various other banal everyday activities involving correspondence with commercial entities.

With a single opt-in they only need to submit their email address to the sign up form once. They are not required to confirm their sign up and are immediately added to the email list.

Opt-in (double)

A double opt-in occurs when a user wishing to subscribe to an email list must confirm their signup before they are officially added to the list. Often, they are sent a confirmation email that contains a link that they must click on to confirm they want to be added to the email list.

While double opt-ins are harder to come by, they are usually much more valuable, since the user is genuinely interested in future correspondence and didn’t just get tricked into joining a mailing list whilst buying tickets to a gig.


“Phishing” is far too kind a name for this terrible and cruel online activity. It involves the baiting of users with imitations of legitimate companies in an attempt to obtain sensitive information (e.g. credit card details, usernames and passwords), often with malicious intent.

The most common techniques these scammers use involve sending spoof emails that look and feel like emails from the companies they are imitating. They then attempt to elicit information from the user by means of manipulated links (URLs with subtle differences to the targeted company) and cloned or imitation websites which prompt the user to enter sensitive information.

Phishing emails are just the worst.


The third version of Post Office Protocol; a method of storing and receiving email which works much like a post office sorting room. It receives and holds email until the recipient “picks it up” and doesn’t store copies after receipt. Due to its simplicity it can be used on many different email programs. It’s important to ensure your phone’s autocorrect doesn’t change it to “Poop3”, or else mass hilarity will ensue. 


For all those who want to know what an email is about without having to actually open it, there is the pre-header. The pre-header is the summary message that appears in text form after the sender name and subject line in an inbox.

While less prominent than either the subject line or sender name, the pre-header can be used to give additional information about the specifics of the marketing email to entice the recipient to open the email, although it is still important to leave things just unclear enough that the recipient might actually want to find out more.

Preview pane

This is a feature that some email clients provide for users in their inbox interface. It shows the user a snippet of the emails in their inbox before they open them so that they can decide whether or not they want to open them. It is basically like watching a trailer for a movie on YouTube before you buy tickets to see it, the key difference being that in most cases a preview pane will not reveal enough key plot elements to ruin your experience.

Responsive design

Emails designed to appear and function in the same way (or at least similarly) on different devices, screen sizes and platforms (because who knows what the next device trend will be… remember when everyone wanted little tiny phones?).

remember when everyone wanted tiny phones?

When effective responsive design is used in creating a marketing email, it should make no difference which type of device it is opened on – it will still look like it was intended to, ensuring a positive user experience.

Sender reputation

In email marketing, as in life, people build a reputation for themselves as they go. For example, if you are a person who regularly punches their friends in the genitals, people will probably be reluctant to make plans with you.

Sender reputations are built in much the same way. If a sender manages their campaigns effectively, sending only strong email content to well-built mailing lists, resulting in low bounce rates and a healthy frequency of having emails flagged as junk, their sender reputation will be good. If a sender manages their campaigns poorly, sending emails which regularly punch people in the genitals, their sender reputation will suffer.

Your sender reputation is important for the effectiveness of your marketing efforts as if you have a bad sender reputation it may prevent your emails from reaching their intended destination. And you may get punched in the genitals, which will not be an ideal outcome. 

Spam (email)

Nobody likes Spam.

Spam emails are broadly defined as those emails which are sent to a recipient who has not solicited them in any way. Typically such emails are commercial in nature, but in many cases they may also include misleading links for phishing purposes. Spam emails differ from marketing emails in that marketing emails are typically sent to a mailing list of people who have “subscribed”, or otherwise given their consent to be emailed by the sender. Which is how it should be, really.

More info:

Sender Policy Framework (SPF) record

Ever received suspiciously spammy emails from an elderly or technologically incompetent relative offering you great prices on erection medications? Guess what? That email may not have actually been sent by that relative on purpose! Hard to believe, we know, but it’s true. Sadly, that relative may not have been using an SPF.

An SPF is a type of domain name service (DNS) record that provides protection for domain holders to prevent spammers from using their domain to send spam emails and affect their sender reputation. This is accomplished by identifying which mail servers are permitted to send email on behalf of that domain, allowing recipient email servers to discern valid messages from invalid ones.

Split testing

Remember that marketing email you designed that you were convinced was amazing and sent to your whole mailing list only to find that it didn’t generate any revenue for some inexplicable reason? Well you probably should have tried split testing before you sent it out, rookie!

In email, split testing is the act of sending out numerous versions of emails following the same theme but containing variations in text, composition, and appearance, then tracking the results based on a number of success metrics to determine the most effective combination of elements for a particular campaign. Such split tests can take the form of A/B split testing, in which two variations of the same email are tested, or multivariate, in which more than two variations are tested.

More info:

Split testing (A/B)

A/B split testing is perfect for when you have 2 variations of an email and aren’t sure which one of the two you should use.  A/B split testing is a process by which two variations of a marketing email are sent to an equal number of recipients to test which variation performs statistically better.

In A/B split testing, only two variations are used. But here’s a question: Why do you have only two variations of your email to test, even though the email contains literally millions of design and linguistic variables? If you think about it, making just two variations of an email is just a weird thing to do. Don’t be weird, go multivariate.

Split testing (multivariate)

Once an email marketer worth his/her salt realises that testing only two variations of an email is a silly and inefficient way to test a campaign, they usually move on to multivariate split testing (like a boss).

Multivariate split testing is a process by which several (more than two) variations of a marketing email are sent to an equal number of recipients to test which variations perform statistically better. In multivariate testing there is no limit to the number of variations that can be tested, allowing testers to check the statistical performance of any and all elements which comprise a marketing email.


Looking for a new and exciting way to be a terrible human being? Well you are sure to love spoofing! Spoofing is a dishonest email practice involving the imitation of legitimate and trusted sources (e.g. banks, social networks, friends), in an attempt to get the user to disclose sensitive information. The imitation can take the form of emails with a falsified sender (phishing), or fraudulent URLs that intend to elicit personal information from users or install malware on their computers.

Yes, there are many ways to spoof in email. Just know that, no matter which one you choose, everyone will hate you forever.

Simple mail transfer protocol (SMTP)

Have you ever wondered what kind of mysterious, incomprehensible universal force transmits your emails so quickly no matter how far away the recipient’s computer may be? Can it be attributed to some sort of mystical wizardry? Nope. It is actually because of (among several other things) SMTP. SMTP is the protocol used to send mail from one mail server to another. Once the mail reaches the recipient’s mail server it is picked up by the client, and made local, using POP or IMAP. Which is all much less fun than magic.

Subject line

In email marketing, the quest for more email opens is one which never ends. And what is the simplest, most effective part of any email to help improve open performance? The subject line, dummy! The subject line is the short message which appears beside an email, after the sender’s name, indicating what the topic of the email is. The subject line is the crux of your campaign’s success. If the subject line isn’t effective, no one will see the content of your email, thus rendering your efforts futile.

Oh yeah – we know a thing or two about subject lines (no doubt). So you should probably book a demo to find out how to become a subject line superhero. Ya heard!


Throttling is definitely the most metal sounding email marketing term. Whilst what throttling actually involves is much less awesome than its name would seem to indicate, it is actually pretty important.

Throttling is the process of controlling the amount email messages that a sender can send to one ISP or mail server at one time. If high volumes of messages are sent from one sending address at one time, the ISP will often bounce these emails. This process is put in place as a precaution against spammers.



For anyone who wants to send a clear message to an email marketer or company that their strategy sucks, there is the unsubscribe. When an email recipient decides that they no longer wish to receive correspondence from a particular sender, they have the option to opt-out of the email dialogue completely. This act is considered an unsubscribe. This can take the form of asking to be removed from a mailing list, cancelling a subscription to a newsletter, or even blocking a sender completely.

According to the latest in scientific research, every time a user unsubscribes from your list, a sad clown sheds a single tear. And then terrifies you in your dreams.

More info:

Have we missed any out? Well, no one’s perfect. Throw other terms we should add into the comments below and we’ll get our thousand monkeys on a thousand typewriters to sort your life out. Awesome!

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