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

営巣[eisou] building a nest
炎症病巣[enshoubyousou] inflamed part
燕巣[ensou] swift's nest (used to make bird's nest soup)
帰巣性[kisousei] homing instinct
空巣狙い[akisunerai] prowler

古巣[furusu] old haunts
精巣[seisou] testicle
青懸巣[aokakesu] blue jay (Cyanocitta cristata)
鼠巣[sosou] rat's nest