The Collaborative International Dictionary of English v.0.48:

Vibrio \Vib"ri*o\, prop. n.; pl. E. Vibrios, L. Vibriones.
   [NL., fr. L. vibrare to vibrate, to move by undulations.]
   (Biol.)
   A genus of motile bacteria characterized by short, slightly
   sinuous filaments and an undulatory motion; also, an
   individual of this genus.
   [1913 Webster]

WordNet (r) 3.0 (2006):

vibrio
    n 1: curved rodlike motile bacterium [syn: vibrio, vibrion]