凸とつ形けい

noun which may take the genitive case particle 'no', noun

convex shape; convex

Technical term used in geometry, optics, and engineering to describe a surface or shape that curves outward. Often contrasted with 凹形 (concave). The glosses 'cuspid' and 'gibbous' are rare or specialized; the core meaning is simply 'convex'.

See also: 凸型

Antonyms: 凹形

• このレンズは凸とつ形けいになっている。

  This lens has a convex shape.

• 凸とつ形けいの鏡かがみを使つかうと、広ひろい範はん囲いが見みえる。

  Using a convex mirror lets you see a wide area.