lock

verb (MAKE SAFE)

/lɒk/

/lɑːk/

Definition

B2 [T usually + adv/prep] to put something in a safe place and fasten the lock: He locked the confidential documents in his filing cabinet. You really should lock your car (up) or it'll get stolen.Locking and bolting B1 [I or T] to fasten something with a key, or be fastened with a key: Don't forget to lock the door when you go out. If you shut the door it will lock automatically.Locking and bolting

(Definition of lock verb (MAKE SAFE) from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)