Source : Webster's Revised Unabridged Dictionary (1913)

Illation \Il*la"tion\, n. [L. illatio, fr. illatus, used as p.
   p. of inferre to carry or bring in, but from a different
   root: cf. F. illation. See 1st {In-}, and {Tolerate}, and cf.
   {Infer}.]
   The act or process of inferring from premises or reasons;
   perception of the connection between ideas; that which is
   inferred; inference; deduction; conclusion.

         Fraudulent deductions or inconsequent illations from a
         false conception of things.              --Sir T.
                                                  Browne.

Source : WordNet®

illation
     n : the reasoning involved in drawing a conclusion or making a
         logical judgment on the basis of circumstantial evidence
         and prior conclusions rather than on the basis of direct
         observation [syn: {inference}]