The Collaborative International Dictionary of English v.0.48:

Clothespin \Clothes"pin`\ (? or ?), n.
   A forked piece of wood or plastic, or a small device with a
   spring clamp, used for fastening clothes on a line.
   [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

clothespin
    n 1: wood or plastic fastener; for holding clothes on a
         clothesline [syn: clothespin, clothes pin, clothes
         peg]