beanie
noun [ C ] uk/ˈbiː.ni/ us/ˈbiː.ni/
小圆便帽;童帽
a small hat that fits closely to the head
a beanie hat/cap 小圆便帽
Australian English（顶部有小羊毛球的）羊毛帽子
a hat made from wool with a small round wool ball on top
Compare: bobble hat