The Collaborative International Dictionary of English v.0.48:

Start-up \Start"-up`\, a.
   Upstart. [R.] --Walpole.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Start-up \Start"-up`\ (st[aum]rt"[u^]p`), n.
   1. One who comes suddenly into notice; an upstart. [Obs.]
      --Shak.
      [1913 Webster]

   2. A kind of high rustic shoe. [Obs.] --Drayton.
      [1913 Webster]

            A startuppe, or clownish shoe.        --Spenser.
      [1913 Webster]

WordNet (r) 3.0 (2006):

startup
    n 1: the act of setting in operation; "repeated shutdowns and
         startups are expensive"
    2: the act of starting a new operation or practice; "he opposed
       the inauguration of fluoridation"; "the startup of the new
       factory was delayed by strikes" [syn: inauguration,
       startup]