Английский словарь американских идиом - sign up

{v.} 1. To promise to do something by signing your name; join; sign an agreement. * /We will not have the picnic unless more people sign up./ * /John wants to sign up for the contest./ * /Miss Carter has signed up to be the chaperone at the dance./ 2. To write the name of (a person or thing) to be in an activity; also, to persuade (someone) to do something. * /Betty decided to sign up her dog for obedience training./ * /The superintendent has signed up three new teachers for next year./