Source : Webster's Revised Unabridged Dictionary (1913)

Filler \Fill"er\, n.
   1. (Paint.) A composition, as of powdered silica and oil,
      used to fill the pores and grain of wood before applying
      paint, varnish, etc.

   2. (Forestry) Any standing tree or standard higher than the
      surrounding coppice in the form of forest known as coppice
      under standards. Chiefly used in the pl.

Filler \Fill"er\, n. [From 1st {Fill}.]
   A thill horse. [Prov. Eng.]

Filler \Fill"er\, n.
   One who, or that which, fills; something used for filling.

         'T is mere filler, to stop a vacancy in the hexameter.
                                                  --Dryden.

         They have six diggers to four fillers, so as to keep
         the fillers always at work.              --Mortimer.

Source : WordNet®

filler
     n 1: used for filling cracks or holes in a surface
     2: 100 filler equal 1 forint
     3: copy to fill space between more important articles in the
        layout of a magazine or newspaper
     4: anything added to fill out a whole; "some of the items in
        the collection are mere makeweights" [syn: {makeweight}]
     5: the tobacco used to form the core of a cigar