fluid
fluid — noun
1. any material that can move and pour freely, changing to fit the container it is
any material that can move and pour freely, changing to fit the container it is placed in — water and air are both examples
The nurse removed the fluid from Daichi's knee with a long needle.
countable noun: fluid from a body part (medical context)
Your car needs fresh brake fluid every two years to stay safe.
technical compound noun: brake fluid, coolant fluid
During science class, Roya learned that air is a fluid, just like water.
Rin poured the blue fluid from the beaker into a thin measuring tube for testing.
The hot fluid from the engine flowed through a metal pipe into the cooling tank.
- solid
a substance with a fixed shape that does not flow
文法句型
fluid + verb (flows, leaks, evaporates)
a/the + fluid + of + noun
用法筆記
The noun can be countable (three different fluids were tested) or uncountable (brake fluid needs replacing). In everyday speech, 'liquid' is more common; 'fluid' carries a more technical or medical feel.
常見錯誤
fluid — adjective
1. moving or happening in a smooth, graceful way that has no sudden stops, breaks,
moving or happening in a smooth, graceful way that has no sudden stops, breaks, or awkward moments
The dancer's fluid movements made the whole performance look effortless.
fluid movement (collocation: graceful, continuous motion)
Heloísa speaks French with such a fluid style that listeners assume she is native.
fluid style (collocation: smooth speech or writing)
Tyler's fluid dive into the pool earned him the highest score from the judges.
Isabela's sentences moved in a fluid stream that carried the reader smoothly through the story.
Astrid repeated the same dance step until her movements looked fluid and natural.
- smooth
more general; can describe textures and surfaces, not just motion
- graceful
emphasizes elegance and beauty in movement rather than just continuity
- flowing
very close in meaning; often used for hair, fabric, or water as well
- effortless
focuses on the ease of the movement, not just its continuity
文法句型
fluid + noun (movement, motion, style, writing)
be + fluid (Her dance was fluid.)
用法筆記
Common in descriptions of dance, sports, and artistic performance; also applied to writing and speech. The opposite is 'jerky' or 'stiff'.
常見錯誤
2. not yet set or settled, shifting repeatedly and often doing so without clear war
not yet set or settled, shifting repeatedly and often doing so without clear warning
The peace talks between Ishaan's country and its neighbour remained fluid, with no fixed agreement yet.
remain fluid (collocation: situations that keep shifting)
Christopher said his travel plans are still fluid — he might visit Japan or Brazil.
fluid plans (collocation)
The manager at Naoko's company kept the team schedule fluid so they could shift tasks as needed.
Talia kept the classroom schedule fluid so she could adapt it to her students' needs.
Tamar's career path has been fluid — she moved from teaching into graphic design, then into marketing.
文法句型
be + fluid (The situation is fluid.)
fluid + noun (fluid plans, a fluid boundary)
用法筆記
Predicative use (the situation is fluid) is most frequent. Attributive use (a fluid boundary) also occurs. This sense carries a neutral or slightly cautious tone — it does not mean 'unreliable', only that change is expected.
常見錯誤
3. having a physical nature that allows it to flow easily and change shape, like wa
having a physical nature that allows it to flow easily and change shape, like water or oil rather than like stone or wood
Liam watched the warm maple syrup flow in a fluid stream over his breakfast pancakes.
fluid stream (physical property: pours easily when warm)
The lava from the volcano was so fluid that it raced down the hillside quickly.
At high temperatures glass becomes fluid and can be shaped into new forms.
Cooking oil is more fluid than honey, so it spreads across a pan much faster.
文法句型
fluid + noun (substance, material)
be + fluid (Lava is fluid.)
more fluid than + noun
用法筆記
Distinguish from the noun sense: as an adjective, fluid describes the property of being able to flow, not the substance itself. Used primarily in scientific writing or when comparing the flow properties of different materials.