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

海峡[kaikyou] channel (e.g. between two land masses)
峡谷[kyoukoku] glen
峡部[kyoubu] isthmus
峡湾[kyouwan] fjord
山峡[sankyou] gorge

台湾海峡[taiwankaikyou] Straits of Taiwan
地峡[chikyou] isthmus
間宮海峡[mamiyakaikyou] strait between Sakhalin and the east coast of Siberia
英仏海峡[eifutsukaikyou] the English Channel
峡間[kyoukan] between the mountains