Thysanura

from WordNet (r) 3.0 (2006)

Thysanura
    n 1: firebrats; silverfish; machilids [syn: {Thysanura}, {order
         Thysanura}]

from The Collaborative International Dictionary of English v.0.48

Thysanura \Thys`a*nu"ra\, n. pl. [NL., fr. Gr. ? fringe + ?
   tail.] (Zool.)
   An order of wingless hexapod insects which have setiform
   caudal appendages, either bent beneath the body to form a
   spring, or projecting as bristles. It comprises the Cinura,
   or bristletails, and the Collembola, or springtails. Called
   also {Thysanoura}. See {Lepisma}, and {Podura}.
   [1913 Webster]