The Collaborative International Dictionary of English v.0.48:

Pixy \Pix"y\, Pixie \Pix"ie\, n.; pl. Pixies. [For Pucksy,
   from Puck.]
   1. An old English name for a fairy; an elf. [Written also
      picksy.]
      [1913 Webster]

   2. (Bot.) A low creeping evergreen plant (Pyxidanthera
      barbulata), with mosslike leaves and little white
      blossoms, found in New Jersey and southward, where it
      flowers in earliest spring.
      [1913 Webster]

   Pixy ring, a fairy ring or circle. [Prov. Eng.]

   Pixy stool (Bot.), a toadstool or mushroom. [Prov. Eng.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

pixy
    n 1: creeping evergreen shrub having narrow overlapping leaves
         and early white star-shaped flowers; of the pine barrens of
         New Jersey and the Carolinas [syn: pyxie, pixie,
         pixy, Pyxidanthera barbulata]
    2: (folklore) fairies that are somewhat mischievous [syn: elf,
       hob, gremlin, pixie, pixy, brownie, imp]