Filler /(?)/

Fill·er

Filler

n.
  1. One who, or that which, fills; something used for filling.
    'T is mere filler, to stop a vacancy in the hexameter.
    They have six diggers to four fillers, so as to keep the fillers always at work.
  2. A composition, as of powdered silica and oil, used to fill the pores and grain of wood before applying paint, varnish, etc. (Paint.)
  3. 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. (Forestry)

Filler

n.
  1. A thill horse. [Prov. Eng.]