The Collaborative International Dictionary of English v.0.48:

Emphasize \Em"pha*size\, v. t. [imp. & p. p. Emphasized; p.
   pr. & vb. n. Emphasizing.]
   To utter or pronounce with a particular stress of voice; to
   make emphatic; as, to emphasize a word or a phrase.

The Collaborative International Dictionary of English v.0.48:

emphasizing \emphasizing\ n.
   The act of giving special importance or significance to
   something.

   Syn: accenting.
        [WordNet 1.5] emphatic

WordNet (r) 3.0 (2006):

emphasizing
    n 1: the act of giving special importance or significance to
         something [syn: emphasizing, accenting, accentuation]