Glossary
Welcome to the Glossary! Whether you're already familiar with some of these terms or you're just becoming acquainted, our top-level glossary is a great resource for learning all of the relevant goods. Scroll through the full list below, search by term, or select by individual letter.
Graylisting (or Greylisting)
The practice by email service providers where a mail transfer agent (MTA) temporarily rejects any email from a sender it does not recognize or unknown IP, and sets up a delay in delivery.
Graymail (or Greymail)
This term is used for spam-like emails that fall into the grey area of legitimacy and being unwanted, that users typically don't open or click through – such as marketing alerts and newsletters.