The Collaborative International Dictionary of English v.0.48:

Filament \Fil"a*ment\, n. [F. filament, fr. L. filum thread. See
   File a row.]
   A thread or threadlike object or appendage; a fiber; esp.
   (Bot.), the threadlike part of the stamen supporting the
   anther.
   [1913 Webster]

WordNet (r) 3.0 (2006):

filament
    n 1: a very slender natural or synthetic fiber [syn: fibril,
         filament, strand]
    2: the stalk of a stamen
    3: a threadlike structure (as a chainlike series of cells) [syn:
       filament, filum]
    4: a thin wire (usually tungsten) that is heated white hot by
       the passage of an electric current