The Collaborative International Dictionary of English v.0.48:

Hark \Hark\ (h[aum]rk), v. i. [OE. herken. See Hearken.]
   To listen; to hearken. [Now rare, except in the imperative
   form used as an interjection, Hark! listen.] --Hudibras.
   [1913 Webster]

   Hark away! Hark back! Hark forward! (Sporting), cries
      used to incite and guide hounds in hunting.

   To hark back, to go back for a fresh start, as when one has
      wandered from his direct course, or made a digression.
      [1913 Webster]

            He must have overshot the mark, and must hark back.
                                                  --Haggard.
      [1913 Webster]

            He harked back to the subject.        --W. E.
                                                  Norris.
      [1913 Webster]

WordNet (r) 3.0 (2006):

hark back
    v 1: go back to something earlier; "This harks back to a
         previous remark of his" [syn: hark back, return, come
         back, recall]

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "hark back":
   break back, bring back, bring to mind, call back, call to mind,
   call up, change back, conjure up, cry back, cry back to,
   do a flip-flop, do an about-face, evoke, flip-flop, go back,
   go back over, go back to, look back, mind, recall, recall to mind,
   recapture, recollect, recur to, reevoke, reflect, remember,
   retrace, retrospect, return to, revert to, review,
   review in retrospect, revive, see in retrospect, summon up,
   think back, think of, turn, turn about, turn around, turn back,
   use hindsight