Source : Webster's Revised Unabridged Dictionary (1913)

Willow \Wil"low\, n. [OE. wilowe, wilwe, AS. wilig, welig; akin
   to OD. wilge, D. wilg, LG. wilge. Cf. {Willy}.]
   1. (Bot.) Any tree or shrub of the genus {Salix}, including
      many species, most of which are characterized often used
      as an emblem of sorrow, desolation, or desertion. ``A
      wreath of willow to show my forsaken plight.'' --Sir W.
      Scott. Hence, a lover forsaken by, or having lost, the
      person beloved, is said to wear the willow.

            And I must wear the willow garland For him that's
            dead or false to me.                  --Campbell.

   2. (Textile Manuf.) A machine in which cotton or wool is
      opened and cleansed by the action of long spikes
      projecting from a drum which revolves within a box studded
      with similar spikes; -- probably so called from having
      been originally a cylindrical cage made of willow rods,
      though some derive the term from winnow, as denoting the
      winnowing, or cleansing, action of the machine. Called
      also {willy}, {twilly}, {twilly devil}, and {devil}.

   {Almond willow}, {Pussy willow}, {Weeping willow}. (Bot.) See
      under {Almond}, {Pussy}, and {Weeping}.

   {Willow biter} (Zo["o]l.) the blue tit. [Prov. Eng.]

   {Willow fly} (Zo["o]l.), a greenish European stone fly
      ({Chloroperla viridis}); -- called also {yellow Sally}.

   {Willow gall} (Zo["o]l.), a conical, scaly gall produced on
      willows by the larva of a small dipterous fly ({Cecidomyia
      strobiloides}).

   {Willow grouse} (Zo["o]l.), the white ptarmigan. See
      {ptarmigan}.

   {Willow lark} (Zo["o]l.), the sedge warbler. [Prov. Eng.]

   {Willow ptarmigan} (Zo["o]l.)
      (a) The European reed bunting, or black-headed bunting.
          See under {Reed}.
      (b) A sparrow ({Passer salicicolus}) native of Asia,
          Africa, and Southern Europe.

   {Willow tea}, the prepared leaves of a species of willow
      largely grown in the neighborhood of Shanghai, extensively
      used by the poorer classes of Chinese as a substitute for
      tea. --McElrath.

   {Willow thrush} (Zo["o]l.), a variety of the veery, or
      Wilson's thrush. See {Veery}.

   {Willow warbler} (Zo["o]l.), a very small European warbler
      ({Phylloscopus trochilus}); -- called also {bee bird},
      {haybird}, {golden wren}, {pettychaps}, {sweet William},
      {Tom Thumb}, and {willow wren}.

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

   2. A catkin of the pussy willow.

   3. The game of tipcat; -- also called {pussy cat}.

   {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}.

Source : WordNet®

pussy willow
     n 1: small willow of eastern North America having grayish leaves
          and silky catkins that come before the leaves [syn: {Salix
          discolor}]
     2: much-branched Old World willow having large catkins and
        relatively large broad leaves [syn: {goat willow}, {florist's
        willow}, {Salix caprea}]