The Collaborative International Dictionary of English v.0.48:

Accentuation \Ac*cen`tu*a"tion\, n. [LL. accentuatio: cf. F.
   accentuation.]
   Act of accentuating; applications of accent. Specifically
   (Eccles. Mus.), pitch or modulation of the voice in reciting
   portions of the liturgy.
   [1913 Webster]

WordNet (r) 3.0 (2006):

accentuation
    n 1: the use or application of an accent; the relative
         prominence of syllables in a phrase or utterance
    2: the act of giving special importance or significance to
       something [syn: emphasizing, accenting, accentuation]