The Collaborative International Dictionary of English v.0.48:

Corollary \Cor"ol*la*ry\ (k?r"?l-l?-r?; 277), n.; pl.
   Corollaries (-r?z). [L. corollarium gift, corollary, fr.
   corolla. See Corolla.]
   1. That which is given beyond what is actually due, as a
      garland of flowers in addition to wages; surplus;
      something added or superfluous. [Obs.]
      [1913 Webster]

            Now come, my Ariel; bring a corollary,
            Rather than want a spirit.            --Shak.
      [1913 Webster]

   2. Something which follows from the demonstration of a
      proposition; an additional inference or deduction from a
      demonstrated proposition; a consequence.
      [1913 Webster] Corollate

WordNet (r) 3.0 (2006):

corollary
    n 1: a practical consequence that follows naturally; "blind
         jealousy is a frequent corollary of passionate love"
    2: (logic) an inference that follows directly from the proof of
       another proposition