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

偉才[isai] genius
何才[nansai] how old?
画才[gasai] artistic talent
鬼才[kisai] wizard
賢才[kensai] man of ability

口才[kousai] clever speech
才覚[saikaku] ready wit
才学[saigaku] talent and education
才幹[saikan] ability
才器[saiki] talent