| Email client | Also known as Mail User Agents (MUA). This is the software used by the recipient to send and receive email. |
| Sender | The person sending the email. In the context of this group we are mainly referring to business to user emails send via an ESP, but this can also include user to user emails send via an email client |
| Recipient | The person consuming the email. They will use an email client to read the email sent by the sender. |
| ESP | Email Service Provider: a company used by businesses to send emails to recipients. |
| Email developer | An individual who creates code specifically for email. |
| Email building tools | A tool that will generate email ready HTML code meaning a email can be created without the need of an email developer. This could be drag and drop editor or a framework. |
| Email accessibility | How well an email meets WCAG standards |
| Email performance | How well an email works on a device with a slow processor or slow bandwidth |
| Email Markup | The code that structures and styles content within an email. In an HTML email this is done with HTML for structure and CSS for styling. This can also include structured data via JSON or microdata. |