Wordnet 3.0
ADJECTIVE (2)
1. 
 of or pertaining to accent or stress; 
2. 
 (of verse) having a metric system based on stress rather than syllables or quantity; 
- Example: "accentual poetry is based on the number of stresses in a line"- Example: "accentual rhythm"
The Collaborative International Dictionary of English v.0.48:
Accentual \Ac*cen"tu*al\, a.
   Of or pertaining to accent; characterized or formed by
   accent.
   [1913 Webster]
WordNet (r) 3.0 (2006):
accentual
    adj 1: of or pertaining to accent or stress
    2: (of verse) having a metric system based on stress rather than
       syllables or quantity; "accentual poetry is based on the
       number of stresses in a line"; "accentual rhythm" [ant:
       quantitative, syllabic]