/kɑnˈkævəti/ noun, pl -ties
1 [noncount] : the quality or state of being concave : the quality of being curved inward
the concavity of the lens
2 [count] : a shape that is curved inward : a concave shape
The lower back forms a concavity.
The large concavities along the wall of the restaurant are like private rooms.
Useful english dictionary. 2012.