Word
fluid
Phoneticsflu·id, stress on the first syllable
US/ˈfɫuəd/
UK/flˈuːɪd/
Definitions
01liquid or gas
B2 · Upper Intermediate Countable noun Science Technical
n. any substance that flows easily and takes the shape of its container, such as water or air.
n. a substance, such as a liquid, gas, or plasma, that deforms under shear stress and conforms to the shape of its container.
“The mechanic checked the levels of the brake fluid in the car.”
“The laboratory equipment was designed to measure the viscosity of various industrial fluids under extreme pressure conditions.”
Antonyms
02medical liquids
C1 · Advanced Plural noun Medicine Technical
n. liquids given to a patient, often through a tube in the arm.
n. intravenous solutions administered to a patient to maintain hydration or deliver medication.
“The doctor said the patient needed more fluids to recover from the fever.”
“The nursing staff monitored the administration of intravenous fluids to ensure the patient remained stable after the surgery.”
Synonyms
03changing easily
B2 · Upper Intermediate
adj. likely to change; not fixed or settled.
adj. subject to change or transition; characterized by a lack of fixed structure.
日本語:流動的※
“The travel plans are still fluid because we haven't booked the flights yet.”
“The political situation remained fluid as negotiators struggled to reach a consensus before the midnight deadline.”
04smooth motion
B2 · Upper Intermediate
adj. moving in a smooth and beautiful way.
adj. characterized by a smooth, elegant, and continuous quality of motion.
“The dancer's movements were fluid and graceful.”
“The athlete's fluid running style allowed him to maintain a high pace without appearing to exert significant effort.”
05available cash
C1 · Advanced Formal · Technical
adj. describes money or assets that can be used or moved easily.
adj. referring to assets that are easily converted into cash without significant loss of value.
“The company needs to keep some fluid assets to pay for unexpected repairs.”
“The investment firm advised the client to maintain a portion of their portfolio in fluid capital to respond to market volatility.”
Antonyms
Collocations
Common phrases and expressions where native English speakers use the word “fluid” in context.
Verb
01. drain the fluid
“The surgeon had to drain the fluid from the patient's knee to relieve the pressure.”
verb + noun
02. replenish fluids
“It is essential to replenish fluids after a long run to avoid dehydration.”
verb + noun
03. retain fluid
“Some medications cause the body to retain fluid, leading to swelling in the ankles.”
verb + noun
Adjective
04. fluid motion
“The dancer moved with a fluid motion that captivated the entire audience.”
adj + noun
05. highly fluid
“The political situation remains highly fluid as the election results continue to come in.”
adv + adj
06. viscous fluid
“The machine requires a viscous fluid to ensure the gears are properly lubricated.”
adj + noun
Noun
07. cleaning fluid
“Be careful not to get any cleaning fluid on the wooden surface as it might damage the finish.”
noun + noun
08. intake of fluid
“Doctors recommend an increased intake of fluid during the hot summer months.”
noun + of + noun
Real-World Examples
“Ebola is rare but highly contagious and can be contracted from body fluids such as vomit, blood or semen, including from dead bodies, and from contaminated surfaces and materials such as bedding and clothing.” “Six to eight glasses of fluid a day is normally recommended by the NHS, , external and in a heatwave you could need a lot more.” “At the same time, sweating leads to the loss of fluids and salt and, crucially, the balance between them in the body changes.” Etymology
From Middle English fluid, from Latin fluidus (“flowing; fluid”), from Latin fluō (“to flow”), from Proto-Indo-European bʰleh₁- (“to swell; surge; overflow; run”). Akin to Ancient Greek φλύειν (phlúein, “to swell; overflow”). Not related to English flow, which is a native, inherited word from plew-, but is distantly related from English bleat.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Word family
NOUN
Related words
Domains
- Exam level
- CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.C1 AdvancedIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.7.0–8.0TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 5.0–5.595–113TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.945–990
- Frequency
- Common
- Level
- C1 · AdvancedOxford
- Updated
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QR code
englishreference.com/q/fluid
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「日本語」 data: JMdict (EDRDG), CC BY-SA 4.0