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

亜種[ashu] subspecies
異機種[ikishu] heterogenous equipment
異種[ishu] different kind (species, variety)
育種[ikushu] (plant) breeding
育種家[ikushuka] (plant) breeder

育種所[ikushujo] (plant) nursery
一種[isshu] species
一粒種[hitotsubudane] an only child
種違い[tanechigai] half-brother
艶種[tsuyadane] love affair