一元[ichigen] unitary
一元化[ichigenka] unification
一元的[ichigenteki] monistic
一元論[ichigenron] monism
一次元[ichijigen] one dimensional

一新紀元[isshinkigen] new era
隠元[ingen] beans
隠元豆[ingenmame] common bean (Phaseolus vulgaris)
家元[iemoto] head of a school (of music, dance)
火の元[hinomoto] origin of fire

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