The Collaborative International Dictionary of English v.0.48:

Toleration \Tol`er*a"tion\, n. [L. toleratio: cf. OF.
   toleration.]
   1. The act of tolerating; the allowance of that which is not
      wholly approved.
      [1913 Webster]

   2. Specifically, the allowance of religious opinions and
      modes of worship in a state when contrary to, or different
      from, those of the established church or belief.
      [1913 Webster]

   3. Hence, freedom from bigotry and severity in judgment of
      the opinions or belief of others, especially in respect to
      religious matters.
      [1913 Webster]

WordNet (r) 3.0 (2006):

toleration
    n 1: a disposition to tolerate or accept people or situations;
         "all people should practice toleration and live together in
         peace" [syn: toleration, acceptance, sufferance]
    2: official recognition of the right of individuals to hold
       dissenting opinions (especially in religion)

Bouvier's Law Dictionary, Revised 6th Ed (1856):

TOLERATION. In some. countries, where religion is established by law,
certain sects who do not agree with the established religion are
nevertheless permitted to exist, and this permission is called toleration.
Those are permitted and allowed to remain rather as a matter of favor than a
matter of right.
     2. In the United States, there is no such a thing as toleration, all
men have an equal right to worship God according to the dictates of their
own consciences. See Christianity; Conscience; Religious test.