concave

American  

[kon-keyv, kon-keyv, kon-keyv] / kɒnˈkeɪv, ˈkɒn keɪv, ˈkɒn keɪv /

adjective

1. curved like a segment of the interior of a circle or hollow sphere; hollow and curved.

2. Geometry. (of a polygon) having at least one interior angle greater than 180°.

3. Obsolete. hollow.

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noun

1. a concave surface, part, line, or thing.

2. Machinery. a concave piece, as one against which a drum rotates.

verb (used with object)

concaved, concaving

1. to make concave.

concave British  

/ ˈkɒnkeɪv, kɒnˈkeɪv /

adjective

1. curving inwards

2. physics having one or two surfaces curved or ground in the shape of a section of the interior of a sphere, paraboloid, etc

   a concave lens

3. maths (of a polygon) containing an interior angle greater than 180°

4. an obsolete word for hollow

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verb

1. (tr) to make concave

concave Scientific  

/ kŏn′kāv′ /

1. Curved inward, like the inside of a circle or sphere.

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Other Word Forms

• concavely adverb
• concaveness noun
• subconcave adjective
• subconcavely adverb
• subconcaveness noun

Etymology

Origin of concave

1375–1425; late Middle English (< Middle French ) < Latin concavus, hollow. See con-, cave

Explanation

Concave describes an inward curve; its opposite, convex, describes a curve that bulges outward. They are used to describe gentle, subtle curves, like the kinds found in mirrors or lenses. A valley is a concave curve, a mountain is a convex curve—you can remember this by thinking that things that vex you tend to stick out, and that caves tend to be holes that go in, like valleys or innie belly buttons. If you want to describe a bowl, you might say there is a large blue spot on the center of the concave side.

Example Sentences

It only uses 1.0 gpf, with the help of two strong jets concealed in a concave rim beneath the seat that create a strong swirl during the flush.

From Slate • Feb. 25, 2025

The team synthesized concave, umbrella-like metal complexes that could shield the rotor molecule from unwanted interactions with other molecules in the crystal.

From Science Daily • Sep. 29, 2023

On the top and bottom of the cylinder, the metal had been pushed up in a concave shape, thrust out from pressure on the inside.

From Los Angeles Times • Aug. 3, 2023

The "Walkie Talkie" skyscraper attracted controversy in 2013 when sunlight reflected off its mirrored concave side and melted various parts on a luxury car parked nearby.

From BBC • Mar. 4, 2023

He felt better in the dark because he could not see the beds, where the blankets followed smooth concave outlines; he could not see the photographs in the frames on the bureau.

From "Ceremony:" by Leslie Marmon Silko