Definition:A listserve is an online discussion exchange through email. When you subscribe to a listserve, you receive emails from other members of the listserve as they discuss ideas relating to the topic of the listserve. You can respond to these discussions by replying to any email from the listserve. When you respond, your comment is emailed to every other member of the list. In this way, everyone is updated on the discussion, and they can interact with the other members of the listserve.