baseball jacket
noun [ C ] mainly UK uk/ˈbeɪs.bɔːl ˌdʒæk.ɪt/ us/ˈbeɪs.bɑːl ˌdʒæk.ɪt/ (US usually letterman jacket)
棒球服
a jacket, often with sleeves that are a different colour to the rest of the jacket, that fits tightly round the waist and fastens with a zip