1. Literally, to receive a short message containing information, especially in an office or workplace. Did you get the memo the boss sent around? We're supposed to meet for a team-building exercise after lunch.

2. By extension, to become aware of or informed about a situation, especially one that most or many other people know about already. Often used in or with a negative. Johnny's been dating Sam for over a month now? I guess I didn't get the memo. You're surprised that a giant corporation values its profits over environmental concerns? Didn't you get the memo?