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

一本橋[ipponbashi] (a) log bridge
仮橋[karibashi] temporary bridge
可動橋[kadoukyou] movable bridge
艦橋[kankyou] bridge (e.g. on a warship)
丸木橋[marukibashi] log bridge

橋脚[kyoukyaku] bridge pier
橋脚舟[kyoukyakushuu] pontoon
橋渡し[hashiwatashi] bridge building
橋頭保[kyoutouhou] bridgehead