fluid

[floo-id]

noun

1. a substance, as a liquid or gas, that is capable of flowing and that changes its shape at a steady rate when acted upon by a force tending to change its shape.

adjective

1. pertaining to a substance that easily changes its shape; capable of flowing.

2. consisting of or pertaining to fluids.

3. changing readily; shifting; not fixed, stable, or rigid.

   fluid movements.

4. convertible into cash.

   fluid assets.

fluid

/ ˈfluːɪd /

noun

1. a substance, such as a liquid or gas, that can flow, has no fixed shape, and offers little resistance to an external stress

adjective

1. capable of flowing and easily changing shape

2. of, concerned with, or using a fluid or fluids

3. constantly changing or apt to change

4. smooth in shape or movement; flowing

fluid

1. A state of matter, such as liquid or gas, in which the component particles (generally molecules) can move past one another. Fluids flow easily and conform to the shape of their containers.

2. See also state of matter viscosity

fluid

1. In physics, a substance that flows — usually a liquid or a gas.

Other Word Forms

• fluidal adjective
• fluidly adverb
• fluidally adverb
• fluidness noun
• nonfluid noun
• nonfluidly adverb
• unfluid adjective

Word History and Origins

Origin of fluid¹

First recorded in 1595–1605; from Latin fluidus, equivalent to flu(ere) “to flow” + -idus adjective suffix; -id ⁴

Word History and Origins

Origin of fluid¹

C15: from Latin fluidus , from fluere to flow

Synonym Study

See liquid.

Example Sentences

The 49-year-old is now taking part in research at the Manchester Cancer Research Centre exploring if tear fluid can identify glioblastoma, the most aggressive form of brain tumour.

From BBC

While the Dodgers’ roster discussions remain fluid, Roberts sure made it sound on Friday night like embattled closer Tanner Scott and rookie phenom Roki Sasaki will be on the playoff roster.

From Los Angeles Times

Naturally, you would prefer that your car have a noncritical amount of brake fluid.

From Los Angeles Times

Firstly, even Starmer's biggest fans in government know fluid communication is not his strong point.

From BBC

The 2019 election, also won by Mutharika, was annulled by the country's highest court, which found there had been widespread irregularities, including the use of correction fluid to alter results.

From BBC

Related Words

• flexible 
• shifting www.thesaurus.com
• unsettled 
• unstable