# lock up

CEFR B1 · Phrasal verb

Source: https://englishreference.com/word/lock-up
Updated: 2026-10-22

## Definition

To make a building or room safe by locking all the doors and windows. You usually do this when you are the last person to leave a place.

For teachers: To secure a building or premises by engaging all locks. The verb functions intransitively to describe the act of closing a business for the day or transitively with the building as the object.

## Examples

- Don't forget to lock up when you leave the office.
- The shop owner always stays late to count the money and lock up the store before heading home.
- After the final performance, the stage manager was tasked to lock up the theater, ensuring all fire exits were clear and the main gates were bolted.

## Usage notes

- This phrase is often used without an object when the location is already known to the speaker.
- Teaching tip: Highlight that 'up' adds a sense of completeness to the action, implying that every entrance is secured rather than just one lock.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.