wrist·band /ˈrɪs(t)ˌbænd/
  袖口
  Wrist·band n. The band of the sleeve of a shirt, or other garment, which covers the wrist.
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  wristband
       n 1: band consisting of a part of a sleeve that covers the wrist
       2: a band of cloth or leather or metal links attached to a
          wristwatch and wrapped around the wrist [syn: watchband,
           watchstrap, watch bracelet, bracelet]