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

ない交ぜにする[naimazenisuru] to blend (e.g. truth and lies)
データ交換[deetakoukan] data exchange
メール交換[meerukoukan] exchange of letters
リーダー交代[riidaakoutai] leadership change
意見交換[ikenkoukan] exchange of ideas

一方交通[ippoukoutsuu] one-way traffic
羽交絞め[hagaijime] pinioning
仮名交じり[kanamajiri] mixed writing (characters and kana)
仮名交じり文[kanamajiribun] mixed writing (characters and kana)
賀詞交換[gashikoukan] New Year greetings (parties)

一際[hitokiwa] conspicuously
学際的[gakusaiteki] interdisciplinary
真際[magiwa] on the verge of
金輪際[konrinzai] the deepest bottom of the earth
交際[kousai] company

交際家[kousaika] sociable person
交際嫌い[kousaigirai] unsociable
交際好き[kousaizuki] sociable
交際国[kousaikoku] friendly powers
交際社会[kousaishakai] society