under lock and key

idiom

: 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.

Examples of under lock and key in a Sentence

Recent Examples on the Web

Those who auditioned didn’t use pages of the actual script, which remained under lock and key, but utilized scenes from other movies that required comparable skillsets, like rattling off complex equations. —Zoe Hewitt, Variety, 15 Dec. 2023

Not only are Steward’s hospitals in Massachusetts in particularly dire straits, but Steward has sued state agencies in an effort to keep its finances under lock and key. —Tara Bannow, STAT, 1 Apr. 2024

Items like facial cream, rug shampoo and alcohol are under lock and key. —Letters To The Editor, The Mercury News, 12 Jan. 2024

Editor’s picks According to Gypsy, Dee Dee kept her under lock and key during her childhood and young adulthood, monitoring her communications and keeping her confined to a wheelchair. —Ej Dickson, Rolling Stone, 6 Jan. 2024

Hosted by Nick Cannon and featuring a panel of judges that includes Ken Jeong, Jenny McCarthy, Nicole Scherzinger and Robin Thicke, the show follows a strict set of rules and guidelines to ensure the contestants identities stay under lock and key. —Diane J. Cho, Peoplemag, 21 Dec. 2023

Netflix also employs metrics like completion rate and subscriber retention in its decision-making — and those are likely to stay under lock and key. —Rick Porter, The Hollywood Reporter, 19 Dec. 2023

The crisis has forced supermarkets to put their olive oil supplies under lock and key just to prevent it from being stolen. —Byprarthana Prakash, Fortune Europe, 20 Nov. 2023

Though details remain under lock and key, founding member Mel B let the news slip out during her appearance Tuesday (Jan. 9) on TODAY with Hoda & Jenna. —Lars Brandle, Billboard, 3 Sep. 2019