関係 (kankei) means "relation," "connection," or "relationship." You use it to describe how people or things are linked, or the connection between ideas. It can also refer to personal relationships like friendships or romantic partnerships. For example, 「彼と彼女は良い関係です。」 (He and she have a good relationship.)

物や人のつながり、または関係性について話すときに使います。「彼と彼女は良い関係です。」