Phrase guide

jack nut

noun · 1 senses · updated from the 2026-07-25 local source snapshot

Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.

Sound

Pronunciation

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1

noun

Meaning 1

A type of nut with a sheet metal body that mushrooms outward, on the far side of the hole through the substrate, when the screw is screwed in, thus providing anchoring with only one-sided access to the hole. It is nearly equivalent to the female portion of a molly bolt.

Definition source: English Wiktionary via Wiktextract

Topics: engineering, mechanical-engineering, mechanics, natural-sciences, physical-sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

Broader terms: nut, fastener, hardware

History

Etymology

From the idea that the nut is jacked into its deformed (expanded) state by a jackscrew-like action of the screw. In practice this step is often performed with a tool that screws in and backs out again, and then the final mating screw follows afterward.