fluid

adjective flu·id \ ˈflü-əd \

|Updated on: 16 Jun 2018

Definition of fluid

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 4

fluid assets

—

fluidly

adverb

—

fluidness

noun

See fluid defined for English-language learners

See fluid defined for kids

Examples of fluid in a Sentence

a substance in a fluid state
warm the jam until it is fluid, then spread it over the cake

Recent Examples of fluid from the Web

Lungs Starting at around 9,000 feet, your lungs may begin to swell due to a constriction of blood vessels, which can cause fluid to leak and accumulate.

— brad stulberg, Outside Online, "What Happens to Your Body When You Climb Everest," 11 June 2018
As with most large-scale restaurant projects still in early-stage construction, details like opening dates and menu components remain relatively fluid.

— justin phillips, San Francisco Chronicle, "Celebrity chef Geoffrey Zakarian has grand plans for historic Sonoma property," 11 June 2018
After a traumatic injury, such surgery would have cleaned up skull fractures and relieved pressure on the brain, which commonly swells and accumulates fluid after a blow to the head.

— lizzie wade, Science | AAAS, "South America’s Inca civilization was better at skull surgery than Civil War doctors," 8 June 2018
As the virus turns deadly, fluid fills the lungs, causing coughing and shortness of breath.

— lisa gutierrez, kansascity, "Mice-borne hantavirus kills young mom; here's what you need to know | The Kansas City Star," 23 Apr. 2018
The Tale of the Princess Kaguya (2013), based on a 10th-century Japanese folktale, is a visually flabbergasting work drawn in fluid charcoal strokes and watercolors.

— david sims, The Atlantic, "Remembering Animation's Legendary Isao Takahata," 11 Apr. 2018
The final number facing punitive action remains fluid, the U.S. officials said, but is expected to include at least a half a dozen people under sanctions powers given to the president by Congress.

— author: john hudson, josh dawsey, shane harris, Anchorage Daily News, "Trump administration to impose fresh sanctions against Russia," 4 Apr. 2018
His bat speed and fluid stroke are conducive to contact and average power.

— ted berg, USA TODAY, "Astros offseason report: Club loaded, eyeing a repeat," 24 Feb. 2018
Inspection of the fluid costs $200 as does the changing of the fluid.

— bob weber, chicagotribune.com, "Vinyl wraps make for versatile alternative to new paint," 17 May 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'fluid.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of fluid

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

NEW! Time Traveler

First Known Use: 1603

in the meaning defined at sense 1a

See Words from the same year

fluid Synonyms

Phrases

up in the air;

Other Chemical Engineering Terms

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

fluid

noun

Definition of fluid

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

—

fluidal

play \ˈflü-ə-dᵊl\ adjective

—

fluidally

play \ˈflü-ə-dᵊl-ē\ adverb

—

fluidlike

play \ˈflü-ə-dᵊl-ˌlīk\ adjective

See fluid defined for English-language learners

Examples of fluid in a Sentence

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 of fluid from the Web

My body is getting a high dosage of vitamins and minerals and fluids that it's never experienced — 3,500 milligrams of vitamin C coursing from the IV.

— craig hlavaty, Houston Chronicle, "Feeling the drip, drip, drip of the mobile IV craze," 13 June 2018
In rare cases, edema — when excessive fluid can collect in the air sacs of the lungs — can occur.

— dwight adams, Indianapolis Star, "Here's what you need to know to prevent drownings," 13 June 2018
Severe cases may require IV fluids or hospitalization.

— tresa baldas, Detroit Free Press, "Tainted melons trigger 3 salmonella lawsuits in Midwest," 12 June 2018
Rabies attacks the central nervous system, and the virus is primarily found in the saliva, brain tissues and spinal fluid of a rabid animal, according to the Illinois Department of Public Health.

— erin hegarty, Naperville Sun, "Rabid bat removed from Naperville home," 11 June 2018
Then the model is loaded into a heart simulator: a box filled with pumps and bloodlike fluid.

— erin blakemore, Washington Post, "Surgeons are using 3-D-printed organs to figure out the best way to operate," 11 June 2018
According to Stanford Children's Health, NAS is usually treated with comfort care like swaddling and supportive care like extra calories and intravenous fluids.

— andy marso, kansascity, "More Missouri babies being born in painful withdrawal; supporting mothers is key," 9 June 2018
River Grove Criminal damage Brake fluid was poured onto the driver’s side of a 2013 Ford C-Max parked in the 2400 block of Leyden Avenue on May 29.

— deborah kadin, chicagotribune.com, "Police reports: Dachshund injured after it is attacked by pit bull in Elmwood Park," 8 June 2018
The most traditional theory is that a diverticulum becomes blocked for one reason or another, leading to buildup of bacteria, mucus and fluid.

— andrea k. mcdaniels, baltimoresun.com, "Diverticulitis can cause digestive problems for some," 7 June 2018

Origin and Etymology of fluid

see ¹fluid

NEW! Time Traveler

First Known Use: 1661

in the meaning defined above

See Words from the same year

Other Chemical Engineering Terms

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

FLUID Defined for English Language Learners

fluid

adjective

Definition of fluid for English Language Learners

: 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

fluid

noun

Definition of fluid for English Language Learners

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

FLUID Defined for Kids

fluid

adjective flu·id \ ˈflü-əd \

Definition of fluid for Students

1 : capable of flowing like a liquid or gas

fluid lava

2 : having a graceful or flowing style or appearance

a dancer's fluid movement

—

fluidly

adverb

fluid

noun

Definition of fluid for Students

: 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.

Medical Dictionary

fluid

adjective flu·id \ ˈflü-əd \

medical Definition of fluid

: 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

noun

medical Definition of fluid

: 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