丸まる首くび

noun

round neck; crew neck

Refers to a round neckline, especially on T-shirts and undershirts. Often used attributively as in 丸首シャツ.

• 今日きょうは白しろい丸まる首くびのTシャツを着きている。

  I'm wearing a white round-necked T-shirt today.

• 丸まる首くびの下した着ぎを買かいに行いく。

  I'm going to buy some round-necked underwear.