悪球[akkyuu] hard ball to hit
逸球[ikkyuu] muffed ball
衛星地球局[eiseichikyuukyoku] (satellite) earth station
眼球[gankyuu] eyeball
気球[kikyuu] balloon

球戯[kyuugi] billiards
球技[kyuugi] ball game (e.g. baseball, tennis, soccer)
球菌[kyuukin] coccus
球形[kyuukei] globular or spherical shape

御返し[okaeshi] return gift
ごった返す[gottagaesu] to be in confusion or commotion
引返す[hikikaesu] to repeat
引繰り返る[hikkurikaeru] to be overturned
往き返り[yukikaeri] round trip

往返[ouhen] round trip
押返す[oshikaesu] to force back
恩を仇で返す[onwoadadekaesu] to return evil for good
恩返し[ongaeshi] requital of a favour (favor)
割り返し[warikaeshi] rebate