English Dictionary

concave

/ˈkɒn.keɪv/

adj

curved like the inner surface of a sphere or bowl / (geometry, not comparable, of a polygon) not convex; having at least one internal angle greater than 180 degrees.

The concave mirror reflected the light beams.

意味（1）

curved like the inner surface of a sphere or bowl

意味（2）

(geometry, not comparable, of a polygon) not convex; having at least one internal angle greater than 180 degrees.

意味（3）

(functional analysis, not comparable, of a real-valued function on the reals) satisfying the property that all segments connecting two points on the function's graph lie below the function.

意味（4）

hollow; empty

as concave […] as a worm-eaten nut