其れ共[soretomo] or
と共に[totomoni] together with
ドイツ民主共和国[doitsuminshukyouwakoku] German Democratic Republic (i.e. former East Germany)
ドイツ連邦共和国[doitsurenpoukyouwakoku] Federal Republic of Germany (former West Germany)
ビジネススクール入学共通試験[bijinesusukuurunyuugakukyoutsuushiken] business school entrance test

欧州共同体[oushuukyoudoutai] European Community
共に[tomoni] together
共営[kyouei] joint management
共栄[kyouei] mutual prosperity

これと同じ[koretoonaji] the same as this
と同じ様に[toonajiyouni] in the same way as
安定同位体[anteidouitai] stable isotope
異句同音[ikudouon] in concert
異口同音に[ikudouonni] in one voice

異同[idou] difference
一口同音[ikkudouon] reading in unison
一視同仁[isshidoujin] loving every human being with impartiality
一心同体[isshindoutai] being one in body and soul
一同[ichidou] all present

医界[ikai] medical world
医学界[igakukai] medical world
黄金世界[ougonsekai] utopia
下界[gekai] this world
花柳界[karyuukai] red-light district

界隈[kaiwai] neighborhood
界面[kaimen] interface
各界[kakkai] each field
学界[gakkai] academic or scientific world
官界[kankai] bureaucracy

御祖父さん[ojiisan] grandfather
御祖母さん[obaasan] grandmother
遠祖[enso] forefathers
開祖[kaiso] (sect) founder
外祖父[gaisofu] maternal grandfather

共同祖界[kyoudousokai] international settlement
教祖[kyouso] founder of a religious sect
元祖[ganso] originator
お高祖頭巾[okosozukin] kerchief worn by women in former times in Japan in cold weather, covering the whole head (except eyes)
始祖[shiso] founder