The Collaborative International Dictionary of English v.0.48:

amnesty \am"nes*ty\ ([a^]m"n[e^]s*t[y^]), n. [L. amnestia, Gr.
   'amnhsti`a, a forgetting, fr. 'a`mnhstos forgotten,
   forgetful; 'a priv. + mna^sqai to remember: cf. F. amnistie,
   earlier amnestie. See Mean, v.]
   1. Forgetfulness; cessation of remembrance of wrong;
      oblivion.
      [1913 Webster]

   2. An act of the sovereign power granting oblivion, or a
      general pardon, for a past offense, as to subjects
      concerned in an insurrection.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Amnesty \Am"nes*ty\, v. t. [imp. & p. p. Amnestied; p. pr. &
   vb. n. Amnestying.]
   To grant amnesty to.
   [1913 Webster]

WordNet (r) 3.0 (2006):

amnesty
    n 1: a period during which offenders are exempt from punishment
    2: a warrant granting release from punishment for an offense
       [syn: pardon, amnesty]
    3: the formal act of liberating someone [syn: amnesty,
       pardon, free pardon]
    v 1: grant a pardon to (a group of people)

The Devil's Dictionary (1881-1906):

AMNESTY, n.  The state's magnanimity to those offenders whom it would
be too expensive to punish.