The Collaborative International Dictionary of English v.0.48:

Isolate \I"so*late\ ([imac]"s[-o]*l[asl]t or
   [imac]s"[-o]*l[=a]t`), n.
   Something that has been isolated; as, an isolate of a
   powerful antibiotic from a tropical plant; an isolate of
   tuberculosis bacillus from an infected patient.
   [PJC]

The Collaborative International Dictionary of English v.0.48:

Isolate \I"so*late\ ([imac]"s[-o]*l[=a]t or [imac]s"[-o]*l[=a]t;
   277), v. t. [imp. & p. p. Isolated
   ([imac]"s[-o]*l[=a]`t[e^]d); p. pr. & vb. n. Isolating
   ([imac]"s[-o]*l[=a]`t[i^]ng).] [It. isolato, p. p. of isolare
   to isolate, fr. isola island, L. insula. See 2d Isle, and
   cf. Insulate.]
   [1913 Webster]
   1. To place in a detached situation; to place by itself or
      alone; to insulate; to separate from others; as, to
      isolate an infected person from others; to isolate the
      troublemakers in a classroom.
      [1913 Webster +PJC]

            Short isolated sentences were the mode in which
            ancient wisdom delighted to convey its precepts.
                                                  --Bp.
                                                  Warburton.
      [1913 Webster]

   2. (Elec.) To insulate. See Insulate.
      [1913 Webster]

   3. (Chem.) To separate (a substance) from all foreign
      substances; to make pure; to obtain in a free state; as,
      to isolate the desired product from a reaction mixture.
      [1913 Webster +PJC]

   4. (Microbiol.) To obtain a culture of a microorganism in
      pure form (from a complex mixture); as, to isolate
      Eschericia coli from a patient's blood.
      [PJC]

WordNet (r) 3.0 (2006):

isolate
    v 1: place or set apart; "They isolated the political prisoners
         from the other inmates" [syn: isolate, insulate]
    2: obtain in pure form; "The chemist managed to isolate the
       compound"
    3: set apart from others; "The dentist sequesters the tooth he
       is working on" [syn: sequester, sequestrate, keep
       apart, set apart, isolate]
    4: separate (experiences) from the emotions relating to them

Moby Thesaurus II by Grady Ward, 1.0:

138 Moby Thesaurus words for "isolate":
   abrupt, abscind, abstract, alienate, amputate, annihilate, apart,
   avoid, ban, banish, bar, block off, bob, bolt, cast off, cast out,
   clip, cloister, close off, cordon, cordon off, crop, cull,
   cull out, cut, cut adrift, cut away, cut off, cut out, debar,
   delete, depart, deport, detach, detached, disarticulate,
   disconnect, disengage, disjoin, disjoint, dissociate, disunite,
   divide, divorce, dock, eject, eliminate, enisle, enucleate,
   eradicate, estrange, except, excise, exclude, exile, expel,
   extinguish, extirpate, ghettoize, gin, ground, ignore, insulate,
   island, island-hop, isolated, keep apart, keep aside, knock off,
   lay aside, leave, lop, maroon, mutilate, nip, ostracize, pare,
   part, peel, pick out, prune, pull away, pull back, pull out,
   put aside, quarantine, reject, remove, removed, riddle, root out,
   rope off, rule out, screen, seal off, seclude, segregate,
   send to Coventry, separate, sequester, set apart, set aside, sever,
   shave, shear, shun, shut off, shut out, sieve, sift, snub,
   sort out, split, spurn, stamp out, stand aloof, stand apart,
   stand aside, step aside, strike off, strip, strip off, subtract,
   sunder, take off, take out, thrash, thresh, throw off, throw out,
   transport, truncate, unaccompanied, uncouple, unyoke, winnow,
   wipe out, withdraw