天魚[amago] land-locked variety of red-spotted masu trout (Oncorhynchus masou ishikawae)
御天気[otenki] weather
コール天[kooruten] corded velveteen
破天連[pateren] Portuguese Jesuits (in Japan in the 16th century)
天鵝絨[tengajuu] velvet

悪天[akuten] bad weather
悪天候[akutenkou] bad weather
悪天使[akutenshi] evil angels
旭日昇天[kyokujitsushouten] full of vigor and vitality (like the rising sun) (vigour)
一天[itten] the whole sky

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)

行けない[ikenai] wrong
行る[yaru] to send
オリエント急行[orientokyuukou] Orient express
カ行[kagyou] classification for Japanese verb with the dictionary form ending in "ku"
ガ行[gagyou] classification for Japanese verb with the dictionary form ending in "gu"

サ行[sagyou] classification for Japanese verb with the dictionary form ending in "su"
ザ行[zagyou] classification for Japanese verb with the dictionary form ending in "zu"
スパイ行為[supaikoui] espionage
タ行[tagyou] classification for Japanese verb with the dictionary form ending in "tsu"
ダ行[dagyou] classification for Japanese verb with the dictionary form ending in "dzu"

馬酔木[asebi] Japanese andromeda (Pieris japonica)
馬鈴薯[jagaimo] potato (Solanum tuberosum)
じゃじゃ馬[jajauma] restive horse
玖馬[kyuuba] Cuba
トロイの木馬[toroinomokuba] Trojan horse

巴奈馬[panama] Panama
馬克[maruku] mark
羅馬字[roomaji] Latin alphabet
ワープロ馬鹿[waapurobaka] someone whose kanji-writing ability has suffered due to overreliance on the kana-to-kanji conversion systems used to input Japanese text on a computer
愛馬[aiba] favourite horse