凹ます[hekomasu] to dent
凹ませる[hekomaseru] to dent
凹まる[kubomaru] to be low (as a hollow)
凹む[hekomu] to be dented
凹める[kubomeru] to hollow out

凹レンズ[ourenzu] concave lens
凹眼[ougan] cavernous eyes
凹眼鏡[ougankyou] concave glasses
凹型[ougata] concavity

肋骨[abarabone] rib
肋間神経痛[rokkanshinkeitsuu] intercostal neuralgia
肋膜[rokumaku] pleura
肋木[rokuboku] wall bars
肋肉[baraniku] boned rib (esp. of pork or beef)

中肋[chuuroku] midrib
肋凹[rokuou] costal fovea
肋材[rokuzai] lumber (for the ribs of a ship)
肋筋[rokkin] stirrup (in reinforced concrete construction)