The Collaborative International Dictionary of English v.0.48:

Popularize \Pop"u*lar*ize\, v. t. [imp. & p. p. Popularized;
   p. pr. & vb. n. Popularizing.] [Cf. F. populariser.]
   To make popular; to make suitable or acceptable to the common
   people; to make generally known; as, to popularize
   philosophy. "The popularizing of religious teaching."
   --Milman.
   [1913 Webster]

WordNet (r) 3.0 (2006):

popularize
    v 1: cater to popular taste to make popular and present to the
         general public; bring into general or common use; "They
         popularized coffee in Washington State"; "Relativity Theory
         was vulgarized by these authors" [syn: popularize,
         popularise, vulgarize, vulgarise, generalize,
         generalise]
    2: make understandable to the general public; "Carl Sagan
       popularized cosmology in his books" [syn: popularize,
       popularise]