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