informal group
インフォーマルグループ
formal group
https://source.unsplash.com/featured/?informal-group#.png
/suto3/google.iconinformal group
/suto3/Google画像検索.iconinformal group
/suto3/Google定義検索.icon informal group
/suto3/wikipedia.iconinformal group
/suto3/weblio.icon informal group
/suto3/kotobank.icon informal group
/suto3/jisho.icon informal group