The Collaborative International Dictionary of English v.0.48:

Syllable \Syl"la*ble\, n. [OE. sillable, OF. sillabe, F.
   syllabe, L. syllaba, Gr. ? that which is held together,
   several letters taken together so as to form one sound, a
   syllable, fr. ? to take together; ? with + ? to take; cf.
   Skr. labh, rabh. Cf. Lemma, Dilemma.]
   1. An elementary sound, or a combination of elementary
      sounds, uttered together, or with a single effort or
      impulse of the voice, and constituting a word or a part of
      a word. In other terms, it is a vowel or a diphtong,
      either by itself or flanked by one or more consonants, the
      whole produced by a single impulse or utterance. One of
      the liquids, l, m, n, may fill the place of a vowel in a
      syllable. Adjoining syllables in a word or phrase need not
      to be marked off by a pause, but only by such an abatement
      and renewal, or reenforcement, of the stress as to give
      the feeling of separate impulses. See Guide to
      Pronunciation, [sect]275.
      [1913 Webster]

   2. In writing and printing, a part of a word, separated from
      the rest, and capable of being pronounced by a single
      impulse of the voice. It may or may not correspond to a
      syllable in the spoken language.
      [1913 Webster]

            Withouten vice [i. e. mistake] of syllable or
            letter.                               --Chaucer.
      [1913 Webster]

   3. A small part of a sentence or discourse; anything concise
      or short; a particle.
      [1913 Webster]

            Before any syllable of the law of God was written.
                                                  --Hooker.
      [1913 Webster]

            Who dare speak
            One syllable against him?             --Shak.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Syllable \Syl"la*ble\, v. t.
   To pronounce the syllables of; to utter; to articulate.
   --Milton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

syllable
    n 1: a unit of spoken language larger than a phoneme; "the word
         `pocket' has two syllables"

Moby Thesaurus II by Grady Ward, 1.0:

141 Moby Thesaurus words for "syllable":
   Spenserian stanza, allophone, alveolar, antistrophe, antonym,
   apico-alveolar, apico-dental, articulation, aspiration,
   assimilation, atom, bilabial, bit, book, burden, cacuminal, canto,
   cerebral, check, chorus, consonant, continuant, couplet, crumb,
   dental, diphthong, dissimilation, distich, envoi, epenthetic vowel,
   epode, explosive, expression, free form, glide, glottal,
   glottalization, guttural, heptastich, hexastich, homograph,
   homonym, homophone, jot, labial, labialization, labiodental,
   labiovelar, laryngeal, lateral, lexeme, line, lingual,
   linguistic form, liquid, locution, logos, lota,
   manner of articulation, measure, metonym, minimum free form,
   modicum, modification, monophthong, monostich, monosyllable,
   morphophoneme, mute, nasal, occlusive, octastich, octave, octet,
   orthographize, ottava rima, ounce, outspell, palatal,
   parasitic vowel, peak, pentastich, pharyngeal, pharyngealization,
   phone, phoneme, plosive, polysyllable, prothetic vowel, quatrain,
   refrain, retroflex, rhyme royal, segmental phoneme, semivowel,
   septet, sestet, sextet, shred, sonant, sonority, speech sound,
   spell, spell backward, spell out, stanza, stave, stop, strain,
   strophe, surd, syllabic nucleus, syllabic peak, syllabize, synonym,
   tercet, term, terza rima, tetrastich, trace out, transition sound,
   triphthong, triplet, tristich, usage, utterance, velar, verbalism,
   verbum, verse, vocable, vocalic, vocoid, voice, voiced sound,
   voiceless sound, voicing, vowel, whit, word, write out