Wordnet 3.0
ADJECTIVE (5)
1. 
 of or relating to syllables; 
- Example: "syllabic accent"- Example: "syllabic characters each represent a syllable"2. 
 consisting of or using a syllabary; 
- Example: "eskimos of the eastern Arctic have a system of syllabic writing"3. 
 (of verse) having lines based on number of syllables rather than on rhythmical arrangement of stresses or quantities; 
4. 
 consisting of a syllable or syllables; 
5. 
 (of speech sounds) forming the nucleus of a syllable; 
- Example: "the syllabic 'nl' in 'riddle'"
The Collaborative International Dictionary of English v.0.48:
Syllabic \Syl*lab"ic\, Syllabical \Syl*lab"ic*al\, a. [Gr. ?:
   cf. F. syllabique.]
   1. Of or pertaining to a syllable or syllables; as, syllabic
      accent.
      [1913 Webster]
   2. Consisting of a syllable or syllables; as, a syllabic
      augment. "The syllabic stage of writing." --Earle.
      [1913 Webster]
WordNet (r) 3.0 (2006):
syllabic
    adj 1: of or relating to syllables; "syllabic accent"; "syllabic
           characters each represent a syllable"
    2: consisting of or using a syllabary; "eskimos of the eastern
       Arctic have a system of syllabic writing"
    3: (of verse) having lines based on number of syllables rather
       than on rhythmical arrangement of stresses or quantities
       [ant: accentual, quantitative]
    4: consisting of a syllable or syllables [ant: nonsyllabic,
       unsyllabic]
    5: (of speech sounds) forming the nucleus of a syllable; "the
       syllabic 'nl' in 'riddle'" [ant: nonsyllabic]
Moby Thesaurus II by Grady Ward, 1.0:
103 Moby Thesaurus words for "syllabic":
   accented, alphabetic character, alveolar, apical, apico-alveolar,
   apico-dental, articulated, assimilated, back, barytone, bilabial,
   broad, cacuminal, central, cerebral, character, checked, cipher,
   close, consonant, consonantal, continuant, dental, device,
   dissimilated, dorsal, flat, front, glide, glossal, glottal, graph,
   grapheme, guttural, hard, heavy, high, intonated, labial,
   labiodental, labiovelar, lateral, lax, letter,
   lexigraphic character, light, lingual, liquid, low, mid, monogram,
   monophthongal, muted, narrow, nasal, nasalized, occlusive, open,
   oxytone, palatal, palatalized, pharyngeal, pharyngealized,
   phonemic, phonetic, phonetic character, phonetic symbol, phonic,
   pictographic character, pitch, pitched, posttonic, retroflex,
   rounded, semivowel, sign, soft, sonant, stopped, stressed, strong,
   surd, symbol, tense, thick, throaty, tonal, tonic, twangy,
   unaccented, unrounded, unstressed, velar, vocalic, vocoid, voiced,
   voiceless, vowel, vowellike, weak, wide, writing,
   written character