Source : Webster's Revised Unabridged Dictionary (1913)

Urchin \Ur"chin\, n. [OE. urchon, irchon, a hedgehog, OF.
   ire[,c]on, eri[,c]on, heri?on, herichon, F. h['e]risson, a
   derivative fr. L. ericius, from er a hedgehog, for her; akin
   to Gr. ?. Cf. {Herisson}.]
   1. (Zo["o]l.) A hedgehog.

   2. (Zo["o]l.) A sea urchin. See {Sea urchin}.

   3. A mischievous elf supposed sometimes to take the form a
      hedgehog. ``We 'll dress [them] like urchins, ouphes, and
      fairies.'' --Shak.

   4. A pert or roguish child; -- now commonly used only of a
      boy.

            And the urchins that stand with their thievish eyes
            Forever on watch ran off each with a prize. --W.
                                                  Howitt.

            You did indeed dissemble, you urchin you; but
            where's the girl that won't dissemble for an
            husband?                              --Goldsmith.

   5. One of a pair in a series of small card cylinders,
      arranged around a carding drum; -- so called from its
      fancied resemblance to the hedgehog. --Knight.

   {Urchin fish} (Zo["o]l.), a diodon.