The Collaborative International Dictionary of English v.0.48:

Vocable \Vo"ca*ble\, n. [L. vocabulum an appellation,
   designation, name, fr. vocare to call, fr. vox, vocis, a
   voice, a word: cf. F. vocable. See Voice.]
   A word; a term; a name; specifically, a word considered as
   composed of certain sounds or letters, without regard to its
   meaning.
   [1913 Webster]

         Swamped near to drowning in a tide of ingenious
         vocables.                                --Carlyle.
   [1913 Webster]

WordNet (r) 3.0 (2006):

vocable
    n 1: a word that is spoken aloud [syn: vocable, spoken word]