ローム層[roomusou] stratum of loam
亜成層圏[aseisouken] substratosphere
一層[issou] much more
沖積層[chuusekisou] alluvium
下層[kasou] lower strata (classes)

下層階級[kasoukaikyuu] proletariat
下層社会[kasoushakai] the underworld
下層土[kasoudo] subsoil
化石層[kasekisou] fossil bed
階層[kaisou] class

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

草臥れる[kutabireru] to get tired
遺草[isou] posthumous works
一年草[ichinensou] annual (plant)
詠草[eisou] draft poem
下草[shitakusa] undergrowth

仮名草紙[kanazoushi] story in the kana
伽草子[togizoushi] fairy-tale book
海草[kaisou] marine plant
乾草[kansou] hay
甘草[kanzou] liquorice