Source : Webster's Revised Unabridged Dictionary (1913)

Xiphosura \Xiph`o*su"ra\, n. pl.
   See {Xiphura}.

Xiphura \Xi*phu"ra\, n. pl. [NL., from Gr. xi`fos sword + ?
   tail.] (Zo["o]l.)
   Same as {Limuloidea}. Called also {Xiphosura}.

   {X ray}. See under {Ray}.

Source : WordNet®

Xiphosura
     n : horseshoe crabs and extinct forms [syn: {order Xiphosura}]