The Collaborative International Dictionary of English v.0.48:

Source \Source\, n. [OE. sours, OF. sourse, surse, sorse, F.
   source, fr. OF. sors, p. p. of OF. sordre, surdre, sourdre,
   to spring forth or up, F. sourdre, fr. L. surgere to lift or
   raise up, to spring up. See Surge, and cf. Souse to
   plunge or swoop as a bird upon its prey.]
   1. The act of rising; a rise; an ascent. [Obs.]
      [1913 Webster]

            Therefore right as an hawk upon a sours
            Up springeth into the air, right so prayers . . .
            Maken their sours to Goddes ears two. --Chaucer.
      [1913 Webster]

   2. The rising from the ground, or beginning, of a stream of
      water or the like; a spring; a fountain.
      [1913 Webster]

            Where as the Poo out of a welle small
            Taketh his firste springing and his sours.
                                                  --Chaucer.
      [1913 Webster]

            Kings that rule
            Behind the hidden sources of the Nile. --Addison.
      [1913 Webster]

   3. That from which anything comes forth, regarded as its
      cause or origin; the person from whom anything originates;
      first cause.
      [1913 Webster]

            This source of ideas every man has wholly in
            himself.                              --Locke.
      [1913 Webster]

            The source of Newton's light, of Bacon's sense.
                                                  --Pope.
      [1913 Webster]

   Syn: See Origin.
        [1913 Webster]

The Free On-line Dictionary of Computing (17 December 2009):

source code
source
source language

    (Or "source", or rarely "source
   language") The form in which a computer program is written by
   the programmer.  Source code is written in some formal
   programming language which can be compiled automatically into
   object code or machine code or executed by an
   interpreter.

   (1995-01-05)


The Jargon File (version 4.4.7, 29 Dec 2003):

source
 n.

    [very common] In reference to software, source is invariably shorthand for
    ?source code?, the preferred human-readable and human-modifiable form of
    the program. This is as opposed to object code, the derived binary
    executable form of a program. This shorthand readily takes derivative
    forms; one may speak of ?the sources of a system? or of ?having source?.


Moby Thesaurus II by Grady Ward, 1.0:

119 Moby Thesaurus words for "source":
   adviser, ambition, announcer, annunciator, antecedent, aspiration,
   author, authority, authorship, basis, begetter, beginning,
   birthplace, bonanza, calling, cause, channel, commencement,
   communicant, communicator, conception, consideration, cornucopia,
   creator, dawn, dawning, derivation, determinant, documentation,
   enlightener, expert witness, font, fount, fountain, fountainhead,
   genesis, goal, gold mine, gossipmonger, grapevine, grass roots,
   ground, guiding light, guiding star, head, headstream, headwater,
   headwaters, ideal, inception, informant, information center,
   information medium, informer, inspiration, intention, interviewee,
   lode, lodestar, mainspring, matter, mine, monitor, mother, motive,
   mouthpiece, newsmonger, notifier, onset, opening, origin, original,
   origination, originator, outset, parent, paternity, press,
   principle, provenance, provenience, public relations officer,
   publisher, quarry, radical, radio, radix, reason, reporter,
   resource, rise, rising, riverhead, root, roots, rootstock, sake,
   score, source of supply, spokesman, spring, staple, start,
   starting, stem, stock, taproot, television, teller, tipster, tout,
   ulterior motive, vein, vocation, well, wellhead, wellspring,
   whence, witness