Denshi Jisho — Online Japanese dictionary

圏 けん 1: sphere; circle; range;
2: (Mathematical term) category (only in the context of "category theory")
Noun, Noun suffix 
囲い かこい enclosure; paling; storage
Common word, Noun 
圏外 けんがい outside range; outside orbit
Common word, Noun 
圏内 けんない within the sphere
Common word, Noun 
圏域 けんいき sphere (e.g. of knowledge, influence)
Noun 
圏谷 けんこく cirque; corrie; cwm
Noun 
圏点 けんてん circle (for emphasis)
Noun 
圏論 けんろん category theory
Noun 
囲い女 かこいめ mistress
Noun 
囲い者 かこいもの mistress
Noun 
囲い込み かこいこみ enclosure
Noun 
囲い込む かこいこむ to enclose; to impound; to cut off; to corral
Godan verb with mu ending 
囲い女 かこいおんな mistress
Noun 
囲いに入れる かこいにいれる to place in an enclosure
Expression, Ichidan verb 

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