The Collaborative International Dictionary of English v.0.48:

zipper \zip"per\, n.
   1. a device for locking together two toothed edges by means
      of a sliding tab.

   Syn: slide fastener, zip, zip-fastener.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

zipper
    n 1: a fastener for locking together two toothed edges by means
         of a sliding tab [syn: slide fastener, zip, zipper,
         zip fastener]
    v 1: close with a zipper; "Zip up your jacket--it's cold" [syn:
         zip up, zipper, zip] [ant: unzip]