A nice post by the Crabby Office lady which explains quite a few e-mail terms.

Attachment. An image, a video or audio file, or any other sort of data file that is sent along with an e-mail message as an "attachment."

Bcc line. I already talked to you about how to use the Bcc line in a post from this summer, but let me just quickly tell you what it actually is...and then you can go learn how and why to use it.

Bounces. Messages that can't reach their destination, and are returned to you, the sender. There are hard bounces (due to invalid e-mail addresses) and soft bounces (due to temporary conditions, such as full inboxes.)

Domain name. This is the part of an e-mail address that comes after the @ sign. My e-mail address is msftCrabby@hotmail.com, so my domain name is hotmail.com. Yours may be live.com, comcast.net, gmail.com, microsoft.com (all my coworkers) or, if you've purchased your own domain name, your-own-funky-name.com.

Message header. Message headers provide a list of technical details, such as who the message came from, the software used to compose it, and the e-mail servers it passed through on the way to you, the recipient. These details can be useful for identifying problems with e-mail or identifying sources of spam.

Subject line. Not adding one before sending an email is Crabby's eighth biggest e-mail etiquette pet peeve (the first being the infernal Reply All button). The Subject line is where you put the, um, subject of your e-mail message. Sending messages without anything in the subject line is like writing a book without a title: Just don't do it.

Flame mail. An e-mail message that is mean, hot-tempered, curt, or not-so-polite. It raises your hackles and gets under your skin. And unfortunately, it's contagious. Flame mail can rear its ugly, fiery head in regular e-mail, as well an on e-bulletin boards, online discussions, blogs, and so on.

POP3, SMTP, IMAP, & MAPI. These are called "protocols".

For a full read with explanataory links visit the Crabby Office Lady