(1):

(n.) A composition, as of powdered silica and oil, used to fill the pores and grain of wood before applying paint, varnish, etc.

(2):

(n.) One who, or that which, fills; something used for filling.

(3):

(n.) A thill horse.

(4):

(n.) 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.