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¹fluid

adjective flu·id \ˈflü-əd\

: capable of flowing freely like water

—used to describe something that can change easily or that changes often

: having or showing a smooth and easy style

Full Definition of FLUID

a : having particles that easily move and change their relative position without a separation of the mass and that easily yield to pressure : capable of flowing

b : subject to change or movement <boundaries became fluid>

: characterized by or employing a smooth easy style <the ballerina's fluid movements> <fluid recitation of his lines>

a : available for various uses <a fluid computer program>

b : liquid 4 <fluid assets>

— flu·id·ly adverb

— flu·id·ness noun

See fluid defined for English-language learners

See fluid defined for kids

Origin of FLUID

French or Latin; French fluide, from Latin fluidus, from fluere to flow; akin to Greek phlyzein to boil over

First Known Use: 1603

Related to FLUID

Synonyms: flowing, fluent, liquid

Antonyms: hard, nonliquid, solid

Other Chemical Engineering Terms

alkali, cation, decant, hygroscopic, isotope, oxidize, slurry, solute, viscous

²fluid

noun

: a substance that is able to flow freely : a liquid substance

Full Definition of FLUID

: a substance (as a liquid or gas) tending to flow or conform to the outline of its container

— flu·id·al \ˈflü-ə-d^əl\ adjective

— flu·id·al·ly \-d^əl-ē\ adverb

— flu·id·like \-ˌlīk\ adjective

See fluid defined for English-language learners

First Known Use of FLUID

1661

Other Chemical Engineering Terms

alkali, cation, decant, hygroscopic, isotope, oxidize, slurry, solute, viscous

Rhymes with FLUID

druid

FLUID Defined for Kids

¹fluid

adjective flu·id \ˈflü-əd\

Definition of FLUID for Kids

: capable of flowing like a liquid or gas <fluid lava>

: having a graceful or flowing style or appearance <a dancer's fluid movement>

— flu·id·ly adverb

²fluid

noun

Definition of FLUID for Kids

: something that tends to flow and take the shape of its container

Word Root of FLUID

The Latin word fluere, meaning “to flow,” gives us the root flu. Words from the Latin fluere have something to do with flowing. A fluid is a substance that flows and is usually a liquid. When someone is fluent in a language the words flow out of her or him. Anything superfluous, or extra, has flowed forth beyond what is necessary.