Prefix used in technical and descriptive compounds to indicate a concave or indented shape, as in 凹レンズ (concave lens).
See also: 凹レンズ
A concave lens spreads light.
This terrain is concave-shaped.
unevenness; bumpiness; roughness · imbalance; unevenness; disparity
concave surface; concavity · concave
concave shape; concavity
concavity; hollow; depression
intaglio plate
The kanji 凹 pictographically represents a hollow or indentation. The reading おう is the Sino-Japanese on'yomi.