Source : Webster's Revised Unabridged Dictionary (1913)

Complex \Com"plex\, a. [L. complexus, p. p. of complecti to
   entwine around, comprise; com- + plectere to twist, akin to
   plicare to fold. See {Plait}, n.]
   1. Composed of two or more parts; composite; not simple; as,
      a complex being; a complex idea.

            Ideas thus made up of several simple ones put
            together, I call complex; such as beauty, gratitude,
            a man, an army, the universe.         --Locke.

   2. Involving many parts; complicated; intricate.

            When the actual motions of the heavens are
            calculated in the best possible way, the process is
            difficult and complex.                --Whewell.

   {Complex fraction}. See {Fraction}.

   {Complex number} (Math.), in the theory of numbers, an
      expression of the form a + b[root]-1, when a and b are
      ordinary integers.

   Syn: See {Intricate}.

Complex \Com"plex\, n. [L. complexus]
   Assemblage of related things; collection; complication.

         This parable of the wedding supper comprehends in it
         the whole complex of all the blessings and privileges
         exhibited by the gospel.                 --South.

   {Complex of lines} (Geom.), all the possible straight lines
      in space being considered, the entire system of lines
      which satisfy a single relation constitute a complex; as,
      all the lines which meet a given curve make up a complex.
      The lines which satisfy two relations constitute a
      congruency of lines; as, the entire system of lines, each
      one of which meets two given surfaces, is a congruency.

Source : WordNet®

complex
     n 1: a conceptual whole made up of complicated and related parts;
          "the complex of shopping malls, houses, and roads
          created a new town" [syn: {composite}]
     2: a compound described in terms of the central atom to which
        other atoms are bound or coordinated [syn: {coordination
        compound}]
     3: (psychoanalysis) a combination of emotions and impulses that
        have been rejected from awareness but still influence a
        person's behavior
     4: a whole structure (as a building) made up of interconnected
        or related structures [syn: {building complex}]

complex
     adj : complicated in structure; consisting of interconnected
           parts; "a complex set of variations based on a simple
           folk melody"; "a complex mass of diverse laws and
           customs" [ant: {simple}]