What does "filler" mean?

Filler: One who, or that which, fills; something used for filling. 'T is mere filer, 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.

Additional senses

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

Sources