The Collaborative International Dictionary of English v.0.48:

Nod \Nod\, v. t. [imp. & p. p. Nodded; p. pr. & vb. n.
   Nodding.]
   1. To incline or bend, as the head or top; to make a motion
      of assent, of salutation, or of drowsiness with; as, to
      nod the head.
      [1913 Webster]

   2. To signify by a nod; as, to nod approbation.
      [1913 Webster]

   3. To cause to bend. [Poetic]
      [1913 Webster]

            By every wind that nods the mountain pine. --Keats.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Nodding \Nod"ding\, a.
   Curved so that the apex hangs down; having the top bent
   downward.
   [1913 Webster]

WordNet (r) 3.0 (2006):

nodding
    adj 1: having branches or flower heads that bend downward;
           "nodding daffodils"; "the pendulous branches of a weeping
           willow"; "lilacs with drooping panicles of fragrant
           flowers" [syn: cernuous, drooping, nodding,
           pendulous, weeping]