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

“My chest was concave trying to pull in breath.”

From BBC • Oct. 10, 2024

"To bring this feature to a molecule, I envisioned encapsulating the rotator space by using bulky concave shaped stators."

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

She travelled into the stratosphere on an exhibition trip, where the sky turned deep purple and the stars came out and the misty earth below looked like a huge concave bowl.

From "I, Robot" by Isaac Asimov