海亀[umigame] sea turtle
亀の子[kamenoko] young turtle (tortoise)
亀の手[kamenote] barnacle
亀鑑[kikan] pattern
亀甲[kikkou] tortoise shell

亀頭[kitou] glans (esp. glans penis)
亀裂[kiretsu] crack
水亀[ishigame] any turtle of the genus Mauremys (esp. the Japanese pond turtle, Mauremys japonica)
盲亀[mouki] blind turtle