Noun
Verb (する, intransitive)
1. relation; relationship; connection
そんな関係が今もまだ続いている。That kind of relationship is still continuing even now.
2. participation; involvement; concern
僕には関係がなかった。It had nothing to do with me.
3. influence; effect
時間の関係で、質問は一つだけにします。Because of time constraints, we'll take only one question.
4. sexual relations; sexual relationship
彼は妻に隠れて、別の女性と関係していた。Behind his wife's back, he was sleeping with another woman.
5. related to; connected to
父の仕事関係のようだ。It seems to be something to do with my father's work.