Synonym: clasp, close, fasten, hook, latch, seal, shut. Antonym: unlock. Similar words: block, o'clock, local, locate, location, dock, sock, shock. Meaning: [lɑk /lɒk] 
n. 1. a fastener fitted to a door or drawer to keep it firmly closed 2. a strand or cluster of hair 3. a mechanism that detonates the charge of a gun 4. enclosure consisting of a section of canal that can be closed to control the water level; used to raise or lower vessels that pass through it 5. a restraint incorporated into the ignition switch to prevent the use of a vehicle by persons who do not have the key 6. any wrestling hold in which some part of the opponent's body is twisted or pressured. v. 1. fasten with a lock 2. keep engaged 3. become rigid or immoveable 4. hold in a locking position 5. become engaged or intermeshed with one another 6. hold fast (in a certain state) 7. place in a place where something cannot be removed or someone cannot escape 8. pass by means through a lock in a waterway 9. build locks in order to facilitate the navigation of vessels.
n. 1. a fastener fitted to a door or drawer to keep it firmly closed 2. a strand or cluster of hair 3. a mechanism that detonates the charge of a gun 4. enclosure consisting of a section of canal that can be closed to control the water level; used to raise or lower vessels that pass through it 5. a restraint incorporated into the ignition switch to prevent the use of a vehicle by persons who do not have the key 6. any wrestling hold in which some part of the opponent's body is twisted or pressured. v. 1. fasten with a lock 2. keep engaged 3. become rigid or immoveable 4. hold in a locking position 5. become engaged or intermeshed with one another 6. hold fast (in a certain state) 7. place in a place where something cannot be removed or someone cannot escape 8. pass by means through a lock in a waterway 9. build locks in order to facilitate the navigation of vessels. 
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151. He could swing his key in the lock,but didn't open the door.
152. The lock won't catch.
153. I forced the lock on the cupboard to see what was inside.
154. She eased the key into the lock, anxious not to wake anyone.
155. I keep meaning to put a lock on it, but I never get round to it.
156. Despite all our attempts to break it open, the lock would not yield.
157. Thieves got in by smashing the lock off the door.
158. To make doubly sure they would not be disturbed she turned the key in the lock.
159. If you can't restrain your dog you must lock it up.
160. Time was when we never needed to lock our house at night.
161. It would be just as well to lock the door when you go out.
162. Leave your key with a neighbour in case you lock yourself out one day.
163. She flicked a stray lock of hair off her face.
164. He took out his keys to lock the door. At that very instant the door flew open and a man ran into the room.
165. I will not rest until the murderer is under lock and key. Sentencedict.com
166. It's quite easy to pick the lock on a car door.
167. Inserting the key in the lock, he turned it and pulled the door open.
168. Don't forget to lock the door when you go out.
169. Lock the stable door after the horse has been stolen.
170. I can't force the key into this lock, it won't fit.
171. One company had a virtual lock on all orange juice sales in the state.
172. George took out a bunch of keys and went to work on the complicated lock.
173. Mr Milner persuaded the federal prosecutors not to lock up his client.
174. The burglars must have picked the lock on the back door.
175. They were separately herded into 2 rooms to lock up.
176. I translated this as a mad desire to lock up every single person with HIV.
177. We should have bought a new lock for the front door.
178. I need to fit a lock on the bathroom door.
179. If you don't lock your doors and windows, you'll be a sitting target for burglars.
180. Your new neighbor is known to the police, so you'd better lock your door.