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

辿たどしい[tadotadoshii] with difficulty
辿りつく[tadoritsuku] to struggle on to

辿る[tadoru] to follow (road)
元を辿る[motowotadoru] to trace back to (the origins of something)