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

データの先頭[deetanosentou] beginning of data
一頭[ittou] one large animal (horses, cattle, etc.)
一頭立て[ittoudate] one-horse (carriage)
咽頭[intou] pharynx
駅頭[ekitou] station

音頭[ondo] leading a group of people
会頭[kaitou] society president
街頭[gaitou] in the street
核弾頭[kakudantou] nuclear warhead
巻頭[kantou] opening page of book