The Collaborative International Dictionary of English v.0.48:

System \Sys"tem\, n. [L. systema, Gr. ?, fr. ? to place
   together; sy`n with + ? to place: cf. F. syst[`e]me. See
   Stand.]
   1. An assemblage of objects arranged in regular
      subordination, or after some distinct method, usually
      logical or scientific; a complete whole of objects related
      by some common law, principle, or end; a complete
      exhibition of essential principles or facts, arranged in a
      rational dependence or connection; a regular union of
      principles or parts forming one entire thing; as, a system
      of philosophy; a system of government; a system of
      divinity; a system of botany or chemistry; a military
      system; the solar system.
      [1913 Webster]

            The best way to learn any science, is to begin with
            a regular system, or a short and plain scheme of
            that science well drawn up into a narrow compass.
                                                  --I. Watts.
      [1913 Webster]

   2. Hence, the whole scheme of created things regarded as
      forming one complete plan of whole; the universe. "The
      great system of the world." --Boyle.
      [1913 Webster]

   3. Regular method or order; formal arrangement; plan; as, to
      have a system in one's business.
      [1913 Webster]

   4. (Mus.) The collection of staves which form a full score.
      See Score, n.
      [1913 Webster]

   5. (Biol.) An assemblage of parts or organs, either in animal
      or plant, essential to the performance of some particular
      function or functions which as a rule are of greater
      complexity than those manifested by a single organ; as,
      the capillary system, the muscular system, the digestive
      system, etc.; hence, the whole body as a functional unity.
      [1913 Webster]

   6. (Zool.) One of the stellate or irregular clusters of
      intimately united zooids which are imbedded in, or
      scattered over, the surface of the common tissue of many
      compound ascidians.
      [1913 Webster]

   Block system, Conservative system, etc. See under
      Block, Conservative, etc.
      [1913 Webster] Systematic

WordNet (r) 3.0 (2006):

system
    n 1: instrumentality that combines interrelated interacting
         artifacts designed to work as a coherent entity; "he bought
         a new stereo system"; "the system consists of a motor and a
         small computer"
    2: a group of independent but interrelated elements comprising a
       unified whole; "a vast system of production and distribution
       and consumption keep the country going" [syn: system,
       scheme]
    3: (physical chemistry) a sample of matter in which substances
       in different phases are in equilibrium; "in a static system
       oil cannot be replaced by water on a surface"; "a system
       generating hydrogen peroxide"
    4: a complex of methods or rules governing behavior; "they have
       to operate under a system they oppose"; "that language has a
       complex system for indicating gender" [syn: system, system
       of rules]
    5: an organized structure for arranging or classifying; "he
       changed the arrangement of the topics"; "the facts were
       familiar but it was in the organization of them that he was
       original"; "he tried to understand their system of
       classification" [syn: arrangement, organization,
       organisation, system]
    6: a group of physiologically or anatomically related organs or
       parts; "the body has a system of organs for digestion"
    7: a procedure or process for obtaining an objective; "they had
       to devise a system that did not depend on cooperation"
    8: the living body considered as made up of interdependent
       components forming a unified whole; "exercise helped him get
       the alcohol out of his system"
    9: an ordered manner; orderliness by virtue of being methodical
       and well organized; "his compulsive organization was not an
       endearing quality"; "we can't do it unless we establish some
       system around here" [syn: organization, organisation,
       system]

Moby Thesaurus II by Grady Ward, 1.0:

227 Moby Thesaurus words for "system":
   Anschauung, Copernican universe, Einsteinian universe, MO,
   Newtonian universe, Ptolemaic universe, aggregation, algorithm,
   all, all being, all creation, allness, anality, angle,
   angle of vision, apple-pie order, approach, arrangement, array,
   attack, basis, blueprint, blueprinting, body-build, brand,
   calculation, cast, character, characteristic, characteristics,
   charting, combination, complex, complexion, composition,
   conception, concord, constituents, constitution, contrivance,
   cosmos, course, crasis, created nature, created universe, creation,
   deployment, design, device, dharma, diathesis, discipline,
   disposal, disposition, enterprise, entity, envisagement, ethos,
   everything that is, expanding universe, eye, fashion, fiber,
   figuring, fine fettle, footing, foresight, forethought, form,
   formation, frame, frame of reference, framework, game, genius,
   good condition, good shape, good trim, grain, graphing,
   ground plan, group, guidelines, guise, habit, harmony, hue, humor,
   humors, idea, ilk, integral, integrate, intention, kind, layout,
   light, line, line of action, lines, lineup, long-range plan,
   macrocosm, macrocosmos, makeup, manner, manner of working, mapping,
   marshaling, master plan, means, megacosm, mental outlook, mesh,
   metagalaxy, method, methodicalness, methodology, mode,
   mode of operation, mode of procedure, modus, modus operandi, mold,
   nature, neatness, network, omneity, operations research, order,
   orderliness, organization, outlook, pattern, peace, physique,
   place, plan, planning, planning function, plenum, point of view,
   position, practice, prearrangement, procedure, proceeding, process,
   program, program of action, property, proportion,
   pulsating universe, quality, quiet, quietude, rationalization,
   reference system, regard, regularity, respect, routine, schedule,
   schema, schematism, schematization, scheme, scheme of arrangement,
   set, set-up, setup, side, sidereal universe, sight, situation,
   slant, somatotype, sort, spirit, stamp, stand, standpoint,
   steady-state universe, strategic plan, strategy, streak, stripe,
   structure, style, suchness, sum, sum of things, symmetry,
   systematicness, systematization, tack, tactical plan, tactics,
   technique, temper, temperament, tendency, tenor, the big picture,
   the drill, the how, the picture, the way of, tidiness, tone,
   totality, totality of being, tranquillity, trimness, type,
   uniformity, universe, vein, view, viewpoint, way, whole wide world,
   wide world, wise, working plan, world, world without end



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

system
 n.

    1. The supervisor program or OS on a computer.

    2. The entire computer system, including input/output devices, the
    supervisor program or OS, and possibly other software.

    3. Any large-scale program.

    4. Any method or algorithm.

    5. System hacker: one who hacks the system (in senses 1 and 2 only; for
    sense 3 one mentions the particular program: e.g., LISP hacker)


The Free On-line Dictionary of Computing (30 December 2018):

system

   1. The supervisor program or operating system on a
   computer.

   2. The entire computer system, including input/output devices,
   the supervisor program or operating system and possibly
   other software.

   3. Any large program.

   4. Any method or algorithm.

   [Jargon File]