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
欝積[usseki] accumulation (e.g. of emotions, grievances, etc.)
沖積[chuuseki] alluvial
沖積期[chuusekiki] alluvial period
沖積世[chuusekisei] alluvial epoch (i.e. the Holocene epoch)

沖積層[chuusekisou] alluvium
沖積土[chuusekido] alluvial soil
下積み[shitazumi] lowest social strata
求積[kyuuseki] mensuration
経路積分[keirosekibun] path integral (physics)