The Ultimate Glossary: 44 Email Marketing Terms Marketers Must Know

Download Now: Free Email Marketing Planning Template
Jeanne Hopkins
Jeanne Hopkins



Email marketing is a central part of your inbound marketing strategy, but it can be an intimidating tactic to tackle if you're a newbie. Heck, even seasoned email marketers are continually learning new terms (we learned some new ones for this post!) and must keep up to date with ever-changing laws that affect how you do your job. So we put together this glossary of email marketing terms that you can refer back to any time you wonder what they heck a blog post, your boss, or your ESP's documentation is talking about.

marketing glossary depicted by an open book

Download Now: Email Marketing Planning Template 

Email Marketing Glossary: 44 Terms to Know


Acceptable Spam Report Rate - The rate at which you can be reported as SPAM without harming your sender reputation. Anything over 0.1% (1 report per 1000 emails) will get a warning.

Acceptance Rate - The percentage of email messages that are accepted by the mail server. Just because an email is accepted by the mail server does not mean it will get to an inbox.


Blacklist - A list that denotes IP addresses as spammer IPs, impeding email deliverability.

Bounce Rate - The rate at which your emails are not delivered. There are two types of bounces, hard and soft, both of which are defined later in this glossary. An acceptable bounce rate is less than 5%.

Bulk Mail - Large scale email marketing sends in which the same content goes to a large group of people.


CAN-SPAM - Short for 'Controlling the Assault of Non-Solicited Pornography And Marketing Act of 2003,' it's a law that outlines rules for commercial email, establishes requirements for commercial messages, provides email recipients with the right to make you stop emailing them, and lays out consequences for violations of the Act. You can read more about compliance in our post about marketing laws.

Clicks Per Delivered - A percentage measure of the number of clicks divided by the number of emails delivered to the intended inbox.

Clicks Per Open - A percentage measure of the number of clicks divided by the number of opens.

CPM (Cost Per Thousand) - In email marketing, CPM commonly refers to the cost per 1000 names on a given rental list. For example, a rental list priced at $250 CPM would mean that the list owner charges $.25 per email address. We'll get into buying lists later in this post.

CTR (Click-Through Rate) - The percentage (the number of unique clicks divided by the number that were opened) of recipients that click on a given URL in your email.

Conversion Rate - The percentage of recipients who respond to your call-to-action in an email marketing campaign or promotion. This is one measure of your email campaign’s success.


Dedicated IP - In email marketing, it refers to an IP address from which only you send email.

Double Opt-In - The recommended method of building an email list, it requires subscribers to confirm their opt in by clicking a link in a confirmation email or responding to the confirmation email in some other way.


Email Campaign - An email or series of lead nurturing emails designed to accomplish an overall marketing goal.

Email Filter – A technique used to block email based on the sender, subject line, or content of an email.

Email Sponsorships - Buying ad space in an email newsletter or sponsoring a specific article or series of articles. Advertisers pay to have their ad inserted into the body of the email.


False positive - A false positive occurs when a legitimate permission-based email is incorrectly filtered or blocked as spam.


Hard Bounce - A hard bounce is the failed delivery of an email due to a permanent reason like a non-existent, invalid, or blocked email address.

Honey Pot - A planted email address by organizations trying to combat spam that, when a spammer harvests and emails, identifies that sender as a spammer.

House List (or Retention List) - One of your most valuable marketing assets, it's a permission-based list that you built yourself with opt-in subscribers.

HTML Email - Sending HTML email makes it possible to get creative with the design of your emails.


IP Warmup - Sending a progressively increasing number of emails out of an IP address in order to build the IP's reputation.


Landing Page - A lead-capture page on your website that is linked to from an email to provide additional information directly related to products or services promoted in the email's call-to-action.

Levels of Authentication - A way of establishing a sender's identity, and ensure the sender is allowed to send from a given domain.

List Segmentation - Selecting a target audience or group of individuals for whom your email message is relevant. A segmented list means a more targeted and relevant email campaign, thus a higher response rate and less unsubscribes and spam reports.


Open Rate - The percentage of emails opened in an email marketing campaign, or the percentage opened of the total number of emails sent.

Opt-In (or Subscribe) - To opt-in or subscribe to an email list is to choose to receive email communications by supplying your email address to a particular company, website or individual thereby giving them permission to email you. The subscriber can often indicate areas of personal interest (e.g. mountain biking) and/or indicate what types of emails they wish to receive from the sender (e.g. newsletters).

Opt-Out (or Unsubscribe) - When a subscribers chooses not to receive email communications from the sender anymore, and requests removal from your email list. It is legally required that you provide a clear way to opt out in every email you send.


Personalization – Adding elements to your email that are personalized based on information you already know about them. It could refer to addressing the recipient by name, referencing past purchases, or other content unique to each recipient.

Physical Address - The physical, street address of the company sending the email, usually found in the footer of an email. Its inclusion is a legal requirement for all email marketing.

Plain Text Email - An email sent without HTML. You should always give your recipients the option to read emails in either HTML or plain text for better readability.

Privacy Policy - A clear description of a website or company’s policy on the use of information collected from and about website visitors and what they do, and do not do, with the data.


Read or Open Length - A measure of the length of time a person opens the email until they close it.

Rental List (or Acquisition List) - Not a recommended email marketing technique, it is a list of prospects or a targeted group of recipients who have opted in to receive information about certain subjects, usually targeted by something like interest, profession, or demographic information.


Sender Score - A free service of Return Path, it's a reputation rating from 0-100 for every outgoing mail server IP address. Mail servers will check your Sender Score before deciding what to do with your emails. A score of over 90 is good.

Shared IP - A less costly option than a dedicated IP address, it is an IP address from which many people send emails.

Signature File - A tagline or short block of text at the end of an email message that identifies the sender and provides additional information such as company name, physical address, and contact information.

Single Opt-In - A single opt-in list is created when users sign up for email communications, but don't confirm the action. This means they can be signed up for a list by someone else, and as such is not a recommended way to build a healthy email marketing list.

Soft Bounce - A soft bounce is the failed delivery of an email due to a temporary issue, like a full mailbox or an unavailable server.

Spam or UCE (Unsolicited Commercial Email) - Email sent to someone who has not opted-in or given permission to email to the sender. Over 90% of email sent is classified as spam.

Spam Cop - A paid spam service that plants their own emails and monitors who harvests the address and spams it.

Spam Trap - An email address that was once valid, but no longer is. If you email this address, you'll receive a hard bounce notice. When the mail server sees consistent traffic going to the dead email, however, they can turn the email into a spam trap. It will stop returning a hard bounce for the known bad address, and instead accept the message and report the sender as a spammer.

SPF - Short for 'Sender Policy Framework', it's a DNS record that says on whose behalf an IP or domain sends email.


Whitelist - Instead of listing IP addresses to block, a whitelist includes IP addresses that have been approved to deliver email to a recipient.

There is a lot marketers need to know about email marketing, and this glossary only scratches the surface. What other terms would you add to this list? 

Image credit: Horia Varlan

New Call-to-action

Related Articles

We're committed to your privacy. HubSpot uses the information you provide to us to contact you about our relevant content, products, and services. You may unsubscribe from these communications at any time. For more information, check out our Privacy Policy.

Use this template to strategically organize your email marketing.

Marketing software that helps you drive revenue, save time and resources, and measure and optimize your investments — all on one easy-to-use platform