spinous

from WordNet (r) 3.0 (2006)

spinous
    adj 1: having spines; "the dorsal fin is spinous" [syn:
           {spinous}, {spiny}] [ant: {spineless}]
    2: shaped like a spine or thorn [syn: {acanthoid}, {acanthous},
       {spinous}]

from The Collaborative International Dictionary of English v.0.48

Spinous \Spi"nous\, a.
   1. Spinose; thorny.
      [1913 Webster]

   2. Having the form of a spine or thorn; spinelike.
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   {Spinous process of a vertebra} (Anat.), the dorsal process
      of the neural arch of a vertebra; a neurapophysis.
      [1913 Webster]