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Added 9 October 2026

fluid

/ˈfluːɪd/ noun

In Latin: latex, liquidus, fūsilis Wiktionary

noun Definition from Wiktionary (CC BY-SA). Pronunciation from Wiktionary, via Kaikki.org. More about fluid at Wordnik → Where our words come from →

Any substance which can flow with relative ease, tends to assume the shape of its container, and obeys Bernoulli's principle; a liquid, gas or plasma.
A liquid (as opposed to a solid or gas).
Intravenous fluids.

adjective

Of or relating to fluid.
In a state of flux; subject to change.
Moving smoothly, or giving the impression of a liquid in motion.

Origin

From Middle English fluid, from Latin fluidus (“flowing; fluid”), from Latin fluō (“to flow”), from Proto-Indo-European *bʰleh₁- (“to swell; surge; overflow; run”). Akin to Ancient Greek φλύειν (phlúein, “to swell; overflow”). Not related to English flow, which is a native, inherited word from *plew-, but is distantly related from English bleat.

From Wiktionary, via Kaikki.org (CC BY-SA)

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