fluid

1 of 2

adjective

flu·​id ˈflü-əd 

1

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

a long screw that forces the fluid chocolate through fine openings

—Technical Survey

b

: subject to change or movement

boundaries became fluid

2

: characterized by or employing a smooth easy style

the ballerina's fluid movements

fluid recitation of his lines

3

a

: available for various uses

a fluid computer program

b

: liquid sense 4

fluid assets

fluidly adverb

fluidness noun

fluid

2 of 2

noun

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

fluidal

ˈflü-ə-dᵊl 

adjective

fluidally

ˈflü-ə-dᵊl-ē 

adverb

fluidlike

ˈflü-ə-dᵊl-ˌlīk 

adjective

Synonyms

Adjective

• flowing
• fluent
• liquid

Examples of fluid in a Sentence

Adjective

a substance in a fluid state

warm the jam until it is fluid, then spread it over the cake

Noun

Please check the fluids in the car's engine.

She needs to drink plenty of fluids.

Fluid leaked from the car's engine.

a bottle of yellow fluid

Recent Examples on the Web

Adjective

Director István Szabó crafts an elegant aesthetic that feels very reminiscent of 2000s period pieces, flush with fluid camera movements and long, sweeping shots that capture the opulent settings of London’s theaters, grand homes and lavish parties. —Travis Bean, Forbes, 5 Oct. 2024

Several hospitals across the U.S. are grappling with shortages of IV fluid after flooding from Hurricane Helene forced medical fluid manufacturers to halt production. —Megan Cerullo, CBS News, 4 Oct. 2024

Noun

Baxter also makes specialty fluids, such as peritoneal dialysis fluid, which helps patients with kidney failure filter waste from their blood, as well as irrigation fluids, used during procedures to clean or flush wounds. —Mustafa Fattah, NBC News, 3 Oct. 2024

Much as our blood vessels send life-sustaining fluid throughout our bodies, these tunnels convey the precious water that sustains all life in this region. —Martin Broen, Smithsonian Magazine, 1 Oct. 2024

Word History

Etymology

Adjective and Noun

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

First Known Use

Adjective

1603, in the meaning defined at sense 1a

Noun

1661, in the meaning defined above

Phrases Containing fluid

• amniotic fluid
• cerebrospinal fluid
• correction fluid
• drilling fluid
• fluid dram
• fluid mechanics
• fluid ounce
• gender fluid
• lighter fluid
• seminal fluid
• serosal fluid
• serous fluid
• synovial fluid
• tissue fluid
• working fluid

Kids Definition

fluid

1 of 2 adjective

flu·​id ˈflü-əd 

1

a

: capable of flowing like a liquid or gas

b

: likely or tending to change or move

2

: showing a smooth easy style

fluid movements

fluidly adverb

fluidness noun

fluid

2 of 2 noun

: a substance tending to flow or take the shape of its container

liquids and gases are fluids

fluidlike

-ˌlīk 

adjective

Etymology

Adjective

from French fluide or Latin fluidus, both meaning "fluid, able to flow," from Latin fluere "to flow" — related to affluent, fluent, flush entry 2, influence, superfluous

Medical Definition

fluid

1 of 2 adjective

flu·​id ˈflü-əd 

: 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

fluid

2 of 2 noun

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

specifically : one in the body of an animal or plant see cerebrospinal fluid, seminal fluid