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

ゴミ集積場[gomishuusekijou] village garbage collection point
英字集合[eijishuugou] alphabetic character set
家集[kashuu] poet's poetical works
歌集[kashuu] anthology
画集[gashuu] book of paintings in print

会集[kaishuu] audience
解集合[kaishuugou] set of solutions
寄集め[yoseatsume] mish-mash
寄せ集める[yoseatsumeru] to put together
寄り集まる[yoriatsumaru] to gather together