Source : Webster's Revised Unabridged Dictionary (1913)

Maintenance \Main"te*nance\, n. [OF. maintenance. See
   {Maintain}.]
   1. The act of maintaining; sustenance; support; defense;
      vindication.

            Whatsoever is granted to the church for God's honor
            and the maintenance of his service, is granted to
            God.                                  --South.

   2. That which maintains or supports; means of sustenance;
      supply of necessaries and conveniences.

            Those of better fortune not making learning their
            maintenance.                          --Swift.

   3. (Crim. Law) An officious or unlawful intermeddling in a
      cause depending between others, by assisting either party
      with money or means to carry it on. See {Champerty}.
      --Wharton.

   {Cap of maintenance}. See under {Cap}.

Source : WordNet®

maintenance
     n 1: activity involved in maintaining something in good working
          order; "he wrote the manual on car care" [syn: {care}, {upkeep}]
     2: means of maintenance of a family or group
     3: court-ordered support paid by one spouse to another after
        they are separated [syn: {alimony}]
     4: the act of sustaining life by food or providing a means of
        subsistence; "they were in want of sustenance"; "fishing
        was their main sustainment" [syn: {sustenance}, {sustentation},
         {sustainment}, {upkeep}]

Source : Free On-Line Dictionary of Computing

maintenance
     
         The modification of a software product, after
        delivery, to correct faults, to improve performance or other
        attributes, or to adapt the product to a changed environment.
     
        Maintenance is an important part of the {software life-cycle}.
        It is expensive in manpower and resources, and one of the aims
        of {software engineering} is to reduce its cost.
     
        (1996-12-27)