The Collaborative International Dictionary of English v.0.48:

Wristband \Wrist"band\, n.
   The band of the sleeve of a shirt, or other garment, which
   covers the wrist.
   [1913 Webster]

WordNet (r) 3.0 (2006):

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, wristband, watch bracelet, bracelet]