jack-in-the-box

American  

[jak-in-thuh-boks] / ˈdʒæk ɪn ðəˌbɒks /

Or jack-in-a-box

noun

plural

jack-in-the-boxes

1. a toy consisting of a box from which an enclosed figure springs up when the lid is opened.

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jack-in-the-box British  

noun

1. a toy consisting of a figure on a compressed spring in a box, which springs out when the lid is opened

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Etymology

Origin of jack-in-the-box

First recorded in 1545–55

Example Sentences

"As far as anyone knew, the T cell receptor didn't undergo any conformational changes when binding to these antigens. But we found that it does, springing open like a sort of jack-in-the-box."

From Science Daily • Dec. 18, 2025

When I’m gone, they tuck her in, and at 2 a.m., when she pops up like a jack-in-the-box, giggling and whining, they sit with her until she exhausts herself and falls back to sleep.

From Salon • Jul. 29, 2025

Pakistan's jack-in-the-box surprise element now feels akin to a cliche from a bygone era.

From BBC • Feb. 23, 2025

“Magazines; more records; books; memorabilia; programs; CDs; VHS; stacking dolls. There’s a jack-in-the-box with a Barbra inside; a Fabergé-style egg.”

From Los Angeles Times • Dec. 18, 2023

To prove his point, he popped his head back inside the rock and then back out again like some kind of deranged jack-in-the-box.

From "Glitch" by Laura Martin