The Collaborative International Dictionary of English v.0.48:

Possess \Pos*sess"\ (?; 277), v. t. [imp. & p. p. Possessed;
   p. pr. & vb. n. Possessing.] [L. possessus, p. p. of
   possidere to have, possess, from an inseparable prep. (cf.
   Position) + sedere to sit. See Sit.]
   1. To occupy in person; to hold or actually have in one's own
      keeping; to have and to hold.
      [1913 Webster]

            Houses and fields and vineyards shall be possessed
            again in this land.                   --Jer. xxxii.
                                                  15.
      [1913 Webster]

            Yet beauty, though injurious, hath strange power,
            After offense returning, to regain
            Love once possessed.                  --Milton.
      [1913 Webster]

   2. To have the legal title to; to have a just right to; to be
      master of; to own; to have; as, to possess property, an
      estate, a book.
      [1913 Webster]

            I am yours, and all that I possess.   --Shak.
      [1913 Webster]

   3. To obtain occupation or possession of; to accomplish; to
      gain; to seize.
      [1913 Webster]

            How . . . to possess the purpose they desired.
                                                  --Spenser.
      [1913 Webster]

   4. To enter into and influence; to control the will of; to
      fill; to affect; -- said especially of evil spirits,
      passions, etc. "Weakness possesseth me." --Shak.
      [1913 Webster]

            Those which were possessed with devils. --Matt. iv.
                                                  24.
      [1913 Webster]

            For ten inspired, ten thousand are possessed.
                                                  --Roscommon.
      [1913 Webster]

   5. To put in possession; to make the owner or holder of
      property, power, knowledge, etc.; to acquaint; to inform;
      -- followed by of or with before the thing possessed, and
      now commonly used reflexively.
      [1913 Webster]

            I have possessed your grace of what I purpose.
                                                  --Shak.
      [1913 Webster]

            Record a gift . . . of all he dies possessed
            Unto his son.                         --Shak.
      [1913 Webster]

            We possessed our selves of the kingdom of Naples.
                                                  --Addison.
      [1913 Webster]

            To possess our minds with an habitual good
            intention.                            --Addison.
      [1913 Webster]

   Syn: To have; hold; occupy; control; own.

   Usage: Possess, Have. Have is the more general word. To
          possess denotes to have as a property. It usually
          implies more permanence or definiteness of control or
          ownership than is involved in having. A man does not
          possess his wife and children: they are (so to speak)
          part of himself. For the same reason, we have the
          faculties of reason, understanding, will, sound
          judgment, etc.: they are exercises of the mind, not
          possessions.
          [1913 Webster]

WordNet (r) 3.0 (2006):

possess
    v 1: have as an attribute, knowledge, or skill; "he possesses
         great knowledge about the Middle East"
    2: have ownership or possession of; "He owns three houses in
       Florida"; "How many cars does she have?" [syn: own, have,
       possess]
    3: enter into and control, as of emotions or ideas; "What
       possessed you to buy this house?"; "A terrible rage possessed
       her"

Moby Thesaurus II by Grady Ward, 1.0:

133 Moby Thesaurus words for "possess":
   achieve, acquire, appreciate, apprehend, be acquainted with,
   be apprised of, be aware of, be cognizant of, be conscious of,
   be conversant with, be enfeoffed of, be informed, be possessed of,
   be seized of, bear, bedevil, beset, bewitch, boast, captivate,
   carry, catch up, charm, claim, clap hands on, clasp, claw, clench,
   clinch, clutch, cognize, come by, come into, command, compel,
   comprehend, conceive, conceptualize, consume, contain, control,
   demonize, devilize, diabolize, discern, dominate, drain off,
   draw off, drive, embody, embrace, enchant, enjoy, fathom, fill,
   gain, get, get hold of, glom on to, govern, grab, grab hold of,
   grapple, grasp, grip, gripe, hant, haunt, have, have and hold,
   have in hand, have information about, have knowledge of,
   have tenure of, hex, hold, hoodoo, hug, impel, include, infatuate,
   jinx, ken, know, lay hands on, lay hold of, loot, make out, nail,
   nip, nip up, not let go, obsess, obtain, occupy, overlook, own,
   palm, partake, perceive, pillage, pocket, prehend, preoccupy,
   procure, realize, receive, recognize, retain, savvy, secure, see,
   seize, snap up, snatch, spook, squat, squat on, steal, take,
   take by assault, take by storm, take hold of, take possession,
   take possession of, understand, usucapt, voodoo, whip up, win,
   witch, wot, wot of