- [uncountable]
the quality of being concave 凹；凹陷 Rocks exposed to wind often show some degree of concavity. 暴露在风中的岩石经常显示出一定程度的凹度。
- [countable]
a shape or place that curves in 凹形；凹状；凹陷处 a deep concavity in the side of the hill 山坡上的深凹