What does 帽子 (mào zi) mean in English?

Card 159HSK 2010 Level 3159/299
CARD159
PROGRESS53%
帽子
mào zi
hat; cap; CL:頂|顶[ding3]

Reveal: Click/Space/Enter/↑↓/w/s/j/kNavigate: ←→/h/l/a/d