under lock and key

phrase

: in a room, box, etc., that is locked
The jewels are kept under lock and key.
The prisoner is being kept/held under lock and key.

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underload switch
under lock and key
underlook
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Cite this Entry

“Under lock and key.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/under%20lock%20and%20key. Accessed 12 Mar. 2026.

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