2. A tank-top like undershirt that has vertical stripes.
3. Short for "beat her".
2. My beater is so comfortable, I could wear it all the time.
3. I'm so mad I think I'm going to take off my shirt and beater. (this is a double pun because if the guy is wearing a beater under his shirt then he is in the act of beatingwearing a wife beater and he is also going to "beat her".)
"I usually work out in a beater"
"I'm trying to get jacked son, so I can rock a beater this summer and flawse for the mamis."
2. Can be used in combination with other words such as "Gino-Beater" and "Hockey-Beater"
2. That guy Anthony from high school was a big time gino-beater!
Guy 2: Dude, that thing's a fucking beater.