Lock up means to lock everything before leaving (a house, shop or office) or to lock someone or something away, including putting someone in prison. The first meaning is everyday: Who's locking up tonight? In the second, you lock valuables in a safe or talk about a criminal: he was locked up for four years.
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lock up (before leaving); lock up + house/shop/office; lock up + valuables; be locked up (in prison)
- I'm the last one here tonight, so I'll lock up and switch off the lights.
- Before going on holiday, we locked up our jewellery in the safe.
- He stole three cars and was locked up for four years.
What changed
First versionThe last person to leave must close the office on the key.
RevisionThe last person to leave must lock up the office.
English speakers don't say close on the key. The verb for using a key is lock, and when you mean the whole place before leaving, lock up is the natural choice: lock up the office.
Lock out means to leave someone outside without a way in. If the door slams and the keys are inside: I locked myself out. Lock up means you did everything right and locked the place: I locked up and went home.
Your turn
The police caught the thief, and now he's ___ for two years.
Show the answer
locked up — The thief was caught and is spending two years in prison: that's locked up. Locked out means “can't get in”, and a caught thief has exactly the opposite problem.
Describe how you leave home before a holiday. Say what you lock and where you hide valuables.
Before a holiday, I lock up the whole flat and hide my laptop and cash in the wardrobe.
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