The Collaborative International Dictionary of English v.0.48:

Reversal \Re*ver"sal\, a. [See Reverse.]
   Intended to reverse; implying reversal. [Obs.] --Bp. Burnet.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Reversal \Re*ver"sal\, n. [From Reverse.]
   1. The act of reversing; the causing to move or face in an
      opposite direction, or to stand or lie in an inverted
      position; as, the reversal of a rotating wheel; the
      reversal of objects by a convex lens.
      [1913 Webster]

   2. A change or overthrowing; as, the reversal of a judgment,
      which amounts to an official declaration that it is false;
      the reversal of an attainder, or of an outlawry, by which
      the sentence is rendered void. --Blackstone.
      [1913 Webster]

WordNet (r) 3.0 (2006):

reversal
    n 1: a change from one state to the opposite state; "there was a
         reversal of autonomic function"
    2: an unfortunate happening that hinders or impedes; something
       that is thwarting or frustrating [syn: reverse, reversal,
       setback, blow, black eye]
    3: turning in an opposite direction or position; "the reversal
       of the image in the lens" [syn: reversal, turn around]
    4: a decision to reverse an earlier decision [syn: reversal,
       change of mind, flip-flop, turnabout, turnaround]
    5: a judgment by a higher court that the judgment of a lower
       court was incorrect and should be set aside [ant:
       affirmation]
    6: turning in the opposite direction [syn: reversion,
       reverse, reversal, turnabout, turnaround]
    7: the act of reversing the order or place of [syn:
       transposition, reversal]
    8: a major change in attitude or principle or point of view; "an
       about-face on foreign policy" [syn: about-face, volte-
       face, reversal, policy change]