The Collaborative International Dictionary of English v.0.48:

Pussy \Pussy\, n. [Dim. of puss.]
   1. A pet name for a cat; also, an endearing name for a girl.
      [1913 Webster]

   2. A catkin of the pussy willow.
      [1913 Webster]

   3. The game of tipcat; -- also called pussy cat.
      [1913 Webster]

   Pussy willow (Bot.), any kind of willow having large
      cylindrical catkins clothed with long glossy hairs,
      especially the American Salix discolor; -- called also
      glaucous willow, and swamp willow.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Salix discolor
    n 1: small willow of eastern North America having greyish leaves
         and silky catkins that come before the leaves [syn: pussy
         willow, Salix discolor]