lock up

lock up idiom
  1. Close a house or place of work, fastening all the doors and windows, as in The attendant locks up at eleven o'clock every night, or Did you remind Abby to lock up? [Late 1500s]
  2. Invest in something not easily converted into cash, as in Most of their assets were locked up in real estate. [Late 1600s]
  3. lock someone up. Confine or imprison someone, as in The princes were locked up in the Tower of London. [c. 1300]

The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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