営巣[eisou] building a nest
炎症病巣[enshoubyousou] inflamed part
燕巣[ensou] swift's nest (used to make bird's nest soup)
帰巣性[kisousei] homing instinct
空巣狙い[akisunerai] prowler

古巣[furusu] old haunts
精巣[seisou] testicle
青懸巣[aokakesu] blue jay (Cyanocitta cristata)
鼠巣[sosou] rat's nest

空オケ[karaoke] karaoke (singing to taped accompaniment)
ベクトル空間[bekutorukuukan] vector space
茜さす空[akanesasusora] glowing sky
圧搾空気[assakukuuki] compressed air
圧縮空気[asshukukuuki] compressed air

位相空間[isoukuukan] phase space (physics)
宇宙空間[uchuukuukan] outer space
雨空[amazora] rainy sky
英国航空[eikokukoukuu] British Airways
仮想空間[kasoukuukan] virtual space (e.g. in computer graphics)