The Collaborative International Dictionary of English v.0.48:

Organize \Or"gan*ize\ ([^o]r"gan*[imac]z), v. t. [imp. & p. p.
   Organized ([^o]r"gan*[imac]zd); p. pr. & vb. n.
   Organizing ([^o]r"gan*[imac]*z[i^]ng).] [Cf. F. organiser,
   Gr. 'organi`zein. See Organ.]
   1. (Biol.) To furnish with organs; to give an organic
      structure to; to endow with capacity for the functions of
      life; as, an organized being; organized matter; -- in this
      sense used chiefly in the past participle.
      [1913 Webster]

            These nobler faculties of the mind, matter organized
            could never produce.                  --Ray.
      [1913 Webster]

   2. To arrange or constitute in parts, each having a special
      function, act, office, or relation; to systematize; to get
      into working order; -- applied to products of the human
      intellect, or to human institutions and undertakings, as a
      science, a government, an army, a war, etc.
      [1913 Webster]

            This original and supreme will organizes the
            government.                           --Cranch.
      [1913 Webster]

   3. (Mus.) To sing in parts; as, to organize an anthem. [R.]
      --Busby.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

organized \or"gan*ized\ adj.
   1. Same as arranged; as, an organized tour.
      [WordNet 1.5]

   2. Formed into an organization. Opposite of unorganized.
      [Narrower terms: corporate, incorporated]
      [WordNet 1.5]

   3. well-conducted. Opposite of disorganized. Also See:
      systematic.

   Syn: organized.
        [WordNet 1.5]

   4. Arranged according to a system or rule.

   Syn: systematized.
        [WordNet 1.5]

   5. Being a member of or formed into a labor union; -- of
      workers, used especially in the phrase "organized labor".
      Opposite of nonunion.

   Syn: unionized, union.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

organized
    adj 1: formed into a structured or coherent whole [ant:
           unorganised, unorganized]
    2: methodical and efficient in arrangement or function; "how
       well organized she is"; "his life was almost too organized"
       [ant: disorganised, disorganized]
    3: being a member of or formed into a labor union; "organized
       labor"; "unionized workers"; "a unionized shop" [syn:
       organized, organised, unionized, unionised]