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

"She's fluid, she's fluent, I've already spoken about her character and how it's very Manchester United."

Read more on BBC

Mr. Pierce, the author of two previous books on the history of animation and Disney studios, shows through his anecdotes how fluid and improvisational collaboration can be—and how much fun.

Read more on The Wall Street Journal

Parziale recently received the Presidential Early Career Award for Scientists and Engineers in recognition of his research into fluid mechanics at extreme speeds.

Read more on Science Daily

Equihua’s thoughts moved as fluidly as the stream beside us, from the waterlogged memories of her past to the buzzing excitement for where her dreams are leading her next.

Read more on Los Angeles Times

A doctor used a thin needle attached to an ultrasound probe to puncture the follicles and remove fluid that contains an egg within it.

Read more on The Wall Street Journal

Related Words

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