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

アルファ線[arufasen] alpha rays
エックス線[ekkususen] X-ray
サイン曲線[sainkyokusen] sinusoid
スピード線[supiidosen] speed lines
緯線[isen] parallel

一次線輪[ichijisenrin] primary coil
一線[issen] line
一直線[icchokusen] straight line
一番線[ichibansen] track no. 1
一塁線[ichiruisen] first-base line