biker jacket       
noun [ C ] uk/ˈbaɪ.kə ˌdʒæk.ɪt/ us/ˈbaɪ.kɚ ˌdʒæk.ɪt/
 摩托骑手短夹克
a short jacket, usually made of leather, in the style worn by someone who rides a motorcycle
  There was a crowd of people in leather biker jackets.
 I loved the black biker jacket I had in my teens. 我喜欢我十几岁时穿的黑色摩托夹克。 
 - More examples
 - Leather gilets and biker jackets with hot pants give a funky Seventies feel.
 - He fondly remembers his first biker jacket.
 - I love this stylish leather-and-canvas biker jacket.
 - She arrived by taxi wearing a biker jacket and a gold chain.
 - Look in secondhand stores for a cheap old biker jacket.