ちょっと一杯[chottoippai] let's have a quick drink
ばつ一[batsuichi] being once divorced
一向[hitaburu] nothing but
サラダ一皿[saradahitosara] plate of salad

安全第一[anzendaiichi] safety first
一か八か[ichikabachika] sink or swim
一っ走り[hitoppashiri] spin (as in 'take a car for a spin')
一つ一つ[hitotsuhitotsu] one-by-one

御三時[osanji] three-o'clock snack
三鞭酒[shanpen] champagne
球面三角法[kyuumensankakuhou] spherical trigonometry
胸三寸[munesanzun] heart
元三[ganzan] New Year's period (January 1st to 3rd)

五十三次[gojuusantsugi] the 53 Toukaidou stages
向こう三軒[mukousangen] one's next three neighbors
降三世明王[gouzanzemyouou] Trailokyavijaya Vidya-raja
再三[saisan] again and again
再三再四[saisansaishi] repeatedly

グループ分離キャラクタ[guruupubunrikyarakuta] group separator
システム分析[shisutemubunseki] systems analysis
ファイル分離キャラクタ[fairubunrikyarakuta] file separator
ユニット分離キャラクタ[yunittobunrikyarakuta] unit separator
レコード分離キャラクタ[rekoodobunrikyarakuta] record separator

異分子[ibunshi] outsider
医薬分業[iyakubungyou] separation of medical and dispensary practice (practise)
一回分[ikkaibun] dose
一部分[ichibubun] part
一分[ichibu] one tenth