助番[sukeban] leader of a female gang
ブロック番号[burokkubangou] block number
暗唱番号[anshoubangou] personal identification number
一貫番号[ikkanbangou] serial number
一番[ichiban] best

一番[hitotsugai] pair
一番鶏[ichibandori] first cockcrowing
一番手[ichibante] first player
一番乗り[ichibannori] leader of a charge
一番線[ichibansen] track no. 1

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