The Collaborative International Dictionary of English v.0.48:

Overhaul \O`ver*haul"\, v. t. [imp. & p. p. Overhauled; p. pr.
   & vb. n. Overhauling.]
   1. To haul or drag over; hence, to turn over for examination;
      to inspect; to examine thoroughly with a view to
      corrections or repairs.
      [1913 Webster]

   2. (Naut.) To gain upon in a chase; to overtake.
      [1913 Webster]

   3. To repair thoroughly; to make repairs on; -- usually
      implying major repairs and perhaps modifying improvements.
      [PJC]

   To overhaul a tackle, to pull on the leading parts so as to
      separate the blocks.

   To overhaul running rigging, to keep it clear, and see that
      no hitch occurs.
      [1913 Webster] Overhaul

The Collaborative International Dictionary of English v.0.48:

Overhaul \O"ver*haul`\, Overhauling \O`ver*haul"ing\, n.
   1. A strict examination with a view to correction or repairs.
      [1913 Webster]

   2. A major repair or a revision for the purpose of
      improvement.
      [PJC]

WordNet (r) 3.0 (2006):

overhaul
    n 1: periodic maintenance on a car or machine; "it was time for
         an overhaul on the tractor" [syn: overhaul, inspection
         and repair, service]
    2: the act of improving by renewing and restoring; "they are
       pursuing a general program of renovation to the entire
       property"; "a major overhal of the healthcare system was
       proposed" [syn: renovation, redevelopment, overhaul]
    v 1: travel past; "The sports car passed all the trucks" [syn:
         pass, overtake, overhaul]
    2: make repairs, renovations, revisions or adjustments to; "You
       should overhaul your car engine"; "overhaul the health care
       system" [syn: overhaul, modernize, modernise]