Acantha

from WordNet (r) 3.0 (2006)

acantha
    n 1: any sharply pointed projection [syn: {spur}, {spine},
         {acantha}]

from The Collaborative International Dictionary of English v.0.48

Acantha \A*can"tha\, n. [Gr. ? thorn, fr. ? point. See {Acute}.]
   1. (Bot.) A prickle.
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   2. (Zool.) A spine or prickly fin.
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   3. (Anat.) The vertebral column; the spinous process of a
      vertebra. --Dunglison.
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