concavity

名词 concavity:

1. a shape that curves or bends inward
   同义词：concave shape, incurvation, incurvature
2. the property possessed by a concave shape
   同义词：concaveness

con.cav.i.ty

n.（名词）
【复数】 con.cav.i.ties
The state of being curved like the inner surface of a sphere.
凹陷：被刻成象球体内表面的样子
A surface or structure configured in such a curve:
被制成这样弯曲的表面或结构：
例句：
.a perfect concavity of white sand lined with palm . . . trees.(Islands)
.一个完美的边上长着棕榈树的白色沙滩.(岛屿)