What is "sign up"

vb. 1 (context transitive English) To add a name to the list of people who are participating in something. 2 (context intransitive English) To add one's own name to the list of people who are participating in something (gloss: including amateur, but not professional, teams) 3 (context intransitive English) To agree to purchase some good or service.

1. v. engage by written agreement; "They signed two new pitchers for the next season" [syn: sign, contract, sign on]

2. join a club, an activity, etc. with the intention to join or participate, "Sign up for yoga classes"