The Collaborative International Dictionary of English v.0.48:

Maintenance \Main"te*nance\, n. [OF. maintenance. See
   Maintain.]
   1. The act of maintaining; sustenance; support; defense;
      vindication.
      [1913 Webster]

            Whatsoever is granted to the church for God's honor
            and the maintenance of his service, is granted to
            God.                                  --South.
      [1913 Webster]

   2. That which maintains or supports; means of sustenance;
      supply of necessaries and conveniences.
      [1913 Webster]

            Those of better fortune not making learning their
            maintenance.                          --Swift.
      [1913 Webster]

   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.
      [1913 Webster]

   4. Those actions required for the care of machinery, a
      building, etc., to keep it clean and in proper functioning
      condition, and to prevent or forestall damage due to
      normal use.
      [PJC]

   5. Payments, such as child support or alimony, to a dependent
      child not living with one or to a divorced wife.
      [PJC]

   Cap of maintenance. See under Cap.
      [1913 Webster]

WordNet (r) 3.0 (2006):

maintenance
    n 1: activity involved in maintaining something in good working
         order; "he wrote the manual on car care" [syn: care,
         maintenance, 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, maintenance]
    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, maintenance, upkeep]
    5: the unauthorized interference in a legal action by a person
       having no interest in it (as by helping one party with money
       or otherwise to continue the action) so as to obstruct
       justice or promote unnecessary litigation or unsettle the
       peace of the community; "unlike champerty, criminal
       maintenance does not necessarily involve personal profit"
       [syn: maintenance, criminal maintenance]

The Free On-line Dictionary of Computing (19 January 2023):

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)