[1] : The Collaborative International Dictionary of English v.0.48

pollen \pol"len\, n. l. pollen fine flour, fine dust; cf. gr.
   ?
   1. fine bran or flour. obs. --bailey.
      1913 webster

   2. bot. the fecundating dustlike cells of the anthers of
      flowers. see flower, and illust. of filament.
      1913 webster

   pollen grain bot., a particle or call of pollen.

   pollen mass, a pollinium. --gray.

   pollen sac, a compartment of an anther containing pollen,
      -- usually there are four in each anther.

   pollen tube, a slender tube which issues from the pollen
      grain on its contact with the stigma, which it penetrates,
      thus conveying, it is supposed, the fecundating matter of
      the grain to the ovule.
      1913 webster
see also:
flower filament pollen grain pollen mass pollen sac pollen tube 

[2] : WordNet (r) 2.0

pollen
     n : the fine spores that contain male gametes and that are borne
         by an anther in a flowering plant

[3] : Moby Thesaurus II by Grady Ward, 1.0

23 moby thesaurus words for "pollen":
   androcyte, antheridium, antherozoid, male gamete, milt, protein,
   scum, seed, semen, seminal fluid, sperm, sperm cell, spermagonium,
   spermatic fluid, spermatid, spermatiophore, spermatium,
   spermatocyte, spermatogonium, spermatophore, spermatozoa,
   spermatozoid, spermatozoon

Pollen >> P Words
Pollen, definition of term: Pollen
pollen_pag1.html

Pollen Tube >> P Words
Pollen Tube, definition of term: Pollen Tube
pollen+tube_pag1.html