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

本の[honno] mere
異本[ihon] different edition
一坪本社[hitotsubohonsha] small company headquarters located in Tokyo simply for name value
一本[ippon] one long cylindrical thing
一本気[ippongi] single-minded (esp. personality or person)

一本橋[ipponbashi] (a) log bridge
一本建て[ippondate] (a) single standard
一本松[ipponmatsu] solitary pine tree
一本杉[ipponsugi] (a) solitary cryptomeria tree
一本槍[ipponyari] guiding principle