The Collaborative International Dictionary of English v.0.48:

Collective \Col*lect"ive\, n. (Gram.)
   A collective noun or name.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Collective \Col*lect"ive\, a. [L. collectivus: cf. F.
   collectif.]
   1. Formed by gathering or collecting; gathered into a mass,
      sum, or body; congregated or aggregated; as, the
      collective body of a nation. --Bp. Hoadley.
      [1913 Webster]

   2. Deducing consequences; reasoning; inferring. [Obs.]
      "Critical and collective reason." --Sir T. Browne.
      [1913 Webster]

   3. (Gram.) Expressing a collection or aggregate of
      individuals, by a singular form; as, a collective name or
      noun, like assembly, army, jury, etc.
      [1913 Webster]

   4. Tending to collect; forming a collection.
      [1913 Webster]

            Local is his throne . . . to fix a point,
            A central point, collective of his sons. --Young.
      [1913 Webster]

   5. Having plurality of origin or authority; as, in diplomacy,
      a note signed by the representatives of several
      governments is called a collective note.
      [1913 Webster]

   Collective fruit (Bot.), that which is formed from a mass
      of flowers, as the mulberry, pineapple, and the like; --
      called also multiple fruit. --Gray.
      [1913 Webster]

WordNet (r) 3.0 (2006):

collective
    adj 1: done by or characteristic of individuals acting together;
           "a joint identity"; "the collective mind"; "the corporate
           good" [syn: corporate, collective]
    2: forming a whole or aggregate [ant: distributive]
    3: set up on the principle of collectivism or ownership and
       production by the workers involved usually under the
       supervision of a government; "collective farms"
    n 1: members of a cooperative enterprise

Moby Thesaurus II by Grady Ward, 1.0:

84 Moby Thesaurus words for "collective":
   abstract, accompanying, accordant, agreeing, associate, associated,
   at one with, bland, broad, coacting, coactive, coadjutant,
   coadjuvant, coadunate, coefficient, coincident, collaborative,
   collectivist, collectivistic, collusive, combined, combining,
   commensal, common, communal, communalist, communalistic, communist,
   communistic, communitarian, commutual, concerted, concomitant,
   concordant, concurrent, concurring, conjoint, conniving,
   consilient, conspiratorial, cooperant, cooperating, cooperative,
   coordinate, coworking, ecumenic, featureless, fellow, general,
   generalized, generic, harmonious, harmonized, in common,
   indefinite, indeterminate, joint, meeting, mutual, nebulous,
   neutral, noncompetitive, nonspecific, parasitic, popular, public,
   reciprocal, saprophytic, social, socialistic, societal, symbiotic,
   synchronous, synergetic, synergic, synergistic, uncharacterized,
   uncompetitive, undifferentiated, united, uniting, unspecified,
   vague, wide