- 1[countable] a device that keeps a door, window, lid, etc. shut, usually needing a key to open it She turned the key in the lock. It's a good idea to have locks fitted on all your windows. see combination lock
- 2[countable] a device with a key that prevents a vehicle or machine from being used a bicycle lock a steering lock
- 3[uncountable] a state in which the parts of a machine, etc. do not move
- 4[countable] a section of canal or river with a gate at either end, in which the water level can be changed so that boats can move from one level of the canal or river to another
- 5[countable] a few hairs that hang or lie together on your head John brushed a lock of hair from his eyes. She kept a lock of her mother's hair.
- 6locks [plural] (literary) a person's hair She shook her long, flowing locks.
- 7[singular] a lock (on something) total control of something One company had a virtual lock on all orange juice sales in the state. see armlock, headlock Idioms
including everything He sold the business lock, stock, and barrel.
to open a lock without a key, using something such as a piece of wire The burglars must have picked the lock on the back door.
locked up safely somewhere; in prison We keep our valuables under lock and key. I will not rest until the murderer is under lock and key.
Check pronunciation: lock