concave

 
Pronunciation: /ˈkɒnkeɪv/

adjective

  • having an outline or surface that curves inwards like the interior of a circle or sphere: concave lensesCompare with convex (sense 1).

Derivatives

concavely

adverb

Origin:

late Middle English: from Latin concavus, from con- 'together' + cavus 'hollow'