御中[onaka] stomach
御話中[ohanashichuu] busy (phone)
アル中[aruchuu] alcoholism
π中間子[paichuukanshi] pi meson
暗中[anchuu] in the dark

暗中摸索[anchuumosaku] groping in the dark
意中[ichuu] one's mind
意中の女[ichuunoonna] sweetheart
井の中の蛙大海を知らず[inonakanokawazutaikaiwoshirazu] parochial
一日中[ichinichijuu] all day long

丸砥石[marutoishi] grindstone
合わせ砥[awasedo] double whetstone
青砥[aoto] medium-grade millstone
中砥[nakato] medium-grade millstone
剃刀砥[kamisorido] razor strop

砥石[toishi] whetstone
砥ぐ[togu] to sharpen
油砥石[aburatoishi] oilstone
荒砥[arato] rough grindstone
砥粉[tonoko] polishing powder