The Collaborative International Dictionary of English v.0.48:

Wind-up \Wind"-up`\, n.
   Act of winding up, or closing; a concluding act or part; the
   end.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

windup
    adj 1: operated by a mechanism; "windup toys"
    n 1: a concluding action [syn: completion, culmination,
         closing, windup, mop up]