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

蝶鮫[chouzame] sturgeon (Acipenser mikadoi)
蝶番い[choutsugai] hinge (e.g. on a door)
蝴蝶[kochou] butterfly
蝶蝶[choucho] butterfly
高山蝶[kouzanchou] alpine butterfly

紋白蝶[monshirochou] small cabbage white butterfly (Pieris rapae)
鳳蝶[agehachou] swallowtail butterfly (esp. the citrus swallowtail butterfly, Papilio xuthus)
赤立羽蝶[akatatehachou] red admiral (butterfly)
蝶貝[chougai] silver-lipped pearl oyster (Pinctada maxima)