society; social circles
Refers to the social world or one's social environment, often with a nuance of the company one keeps or the social scene one moves in.
He has a wide social circle.
Learn the rules of social circles.
Compound of 交際 (こうさい, 'association, socializing') and 社会 (しゃかい, 'society'). The exact historical derivation is uncertain, but the combination straightforwardly yields the meaning 'social circles' or 'the society one associates with'.