- 1to face or curve towards the centre Her feet turn in.
- 2(old-fashioned) to go to bed It’s late—I think I’ll turn in.
(informal) to take somebody to the police or somebody in authority because they have committed a crime She threatened to turn him in to the police. He decided to turn himself in.
- 1to give back something that you no longer need You must turn in your pass when you leave the building.
- 2(especially North American English) to give something to somebody in authority They turned in a petition with 80 000 signatures. I haven't even turned in Monday's work yet.
- 3to achieve a score, performance, profit, etc. The champion turned in a superb performance to retain her title.