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)

高が[takaga] it's only ... (something)
意気軒高[ikikenkou] in high spirits
異常高温[ijoukouon] abnormally high temperatures
一斉高[isseidaka] all-round (market) advance
雲高[unkou] height of clouds

円高[endaka] high-valued yen
価値高い[kachitakai] valuable
可能性が高い[kanouseigatakai] very likely
勘定高い[kanjoudakai] calculating
気高い[kedakai] sublime