buoyancy

American  

[boi-uhn-see, boo-yuhn-see] / ˈbɔɪ ən si, ˈbu jən si /

Also buoyance

noun

buoyancies plural

1. the power to float or rise in a fluid; relative lightness.

2. the power of supporting a body so that it floats; upward pressure exerted by the fluid in which a body is immersed.

3. lightness or resilience of spirit.

   Student well-being and buoyancy are especially important because of the relatively high incidence of depression and suicide.

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buoyancy British  

/ ˈbɔɪənsɪ /

noun

1. the ability to float in a liquid or to rise in a fluid

2. the property of a fluid to exert an upward force (upthrust) on a body that is wholly or partly submerged in it

3. the ability to recover quickly after setbacks; resilience

4. cheerfulness

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buoyancy Scientific  

/ boi′ən-sē /

1. The upward force that a fluid exerts on an object that is less dense than itself. Buoyancy allows a boat to float on water and provides lift for balloons.

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buoyancy Cultural  

1. The force that causes objects to float. According to the principle of Archimedes, when a solid is placed in a fluid (a liquid or a gas), it is subject to an upward force equal in magnitude to the weight of the fluid it has displaced.

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Other Word Forms

Derived Forms

• nonbuoyancy
  noun

Inflected Forms

Nouns

• buoyancies
  plural

Etymology

Origin of buoyancy

First recorded in 1705–15; buoy(ant) + -ancy

Explanation

Buoyancy is a quality that makes things float in water. It's also a type of happiness: if you're full of buoyancy, your mood is light and happy. This is a word with two main meanings that fit together well: Both kinds of buoyancy have to do with floating and staying up. The physical kind refers to objects that float instead of sinking in water, like a life raft or a buoy. The other kind of buoyancy is a happy mood, a feeling that nothing can get you down. So whenever you run into the word buoyancy, just think "staying afloat."

Example Sentences

See Examples For:

buoyancy buoyancies

These mush systems are much thicker and less mobile than liquid magma, making it difficult to explain how they could generate supereruptions through simple buoyancy alone.

From Science Daily ● Jun. 28, 2026

Last July, a North Korean civilian tied plastic foam to his body for buoyancy and swam down the Korean Peninsula’s west coast.

From The Wall Street Journal ● Jun. 24, 2026

Kahana advised not to jump in after anyone who falls into water and to instead call 999 for help before throwing them a buoyancy device if one is available.

From BBC ● May 26, 2026

Trading patterns should provide “a natural buoyancy for prices before the cold arrives.”

From Barron's ● Nov. 21, 2025

Lyra saw that three witches were holding a rope looped around a rock, anchoring the great buoyancy of the gas bag to the earth.

From "The Golden Compass" by Philip Pullman

But beneath it all, there are two buoyancies.

From Time Magazine Archive

Abandoned ideals and buoyancies can be seen within.

From Time Magazine Archive

Related Words

• elasticity
• resilience