Filler

In general, a filler is something that is used to fill gaps. Specialized meanings include:

Materials

 * Filler (animal food), dietary fiber and other ingredients added to pet foods to provide bulk
 * Filler (materials), particles added to a matrix material, usually to improve its properties
 * Filler (packaging), a machine designed to fill packaging, usually occurs in food packaging
 * Filler metal, metal added in the making of a joint through welding, brazing, or soldering
 * Grain filler, a product that is used to achieve a smooth-textured wood finish
 * Injectable filler, a soft tissue filler injected into the skin to help fill in facial wrinkles
 * Star filler, a plastic insert in computer cables which separates wires

Media and entertainment

 * Filler (media), in television and other media, material that exists outside the story arc to pad out other material
 * "Filler", song by hardcore punk band Minor Threat, from their debut E.P.

Other uses

 * Filler (linguistics), a sound spoken to fill up gaps in utterances
 * Filler (surname)
 * Seat filler, a person who fills an empty seat during an event