The Collaborative International Dictionary of English v.0.48:

Turn-out \Turn"-out`\ (t[^u]rn"out`), n.; pl. Turn-outs
   (t[^u]rn"outs`).
   1. The act of coming forth; a leaving of houses, shops, etc.;
      esp., a quitting of employment for the purpose of forcing
      increase of wages; a strike; -- opposed to lockout.
      [1913 Webster]

   2. A short side track on a railroad, which may be occupied by
      one train while another is passing on a main track; a
      shunt; a siding; a switch.
      [1913 Webster]

   3. That which is prominently brought forward or exhibited;
      hence, an equipage; as, a man with a showy carriage and
      horses is said to have a fine turn-out.
      [1913 Webster]

   4. The aggregate number of persons who have come out, as from
      their houses, for a special purpose; the number in
      attendance at a gathering; as, a light turnout for the
      election.
      [1913 Webster +PJC]

   5. Net quantity of produce yielded.
      [1913 Webster]

   6. A space alongside a highway where vehicles may stop, esp.
      for emergency purposes, or to admire the view.
      [PJC]

WordNet (r) 3.0 (2006):

turnout
    n 1: the group that gathers together for a particular occasion;
         "a large turnout for the meeting"
    2: a part of a road that has been widened to allow cars to pass
       or park [syn: turnout, widening]
    3: a short stretch of railroad track used to store rolling stock
       or enable trains on the same line to pass [syn: siding,
       railroad siding, turnout, sidetrack]
    4: what is produced in a given time period [syn: output,
       outturn, turnout]
    5: a set of clothing (with accessories); "his getup was
       exceedingly elegant" [syn: outfit, getup, rig,
       turnout]
    6: attendance for a particular event or purpose (as to vote in
       an election); "the turnout for the rally"
    7: (ballet) the outward rotation of a dancer's leg from the hip