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

何曜日[nanyoubi] what day?
火曜[kayou] Tuesday
火曜日[kayoubi] Tuesday
灰の水曜日[hainosuiyoubi] Ash Wednesday
金曜[kinyou] Friday

金曜日[kinyoubi] Friday
月曜[getsuyou] Monday
月曜日[getsuyoubi] Monday
黒曜岩[kokuyougan] obsidian
黒曜石[kokuyouseki] obsidian

火燵掛布[kotatsugake] cover for kotatsu
火燵布団[kotatsubuton] cover for kotatsu
引火[inka] catching fire
引火温度[inkaondo] flash temperature
引火点[inkaten] flash point

曳火弾[eikadan] tracer bullet
煙火[enka] smoke and fumes (e.g. from cooking)
遠火[toobi] distant fire
下火[shitabi] burning low
下火になる[shitabininaru] to be under control