n.
Pronunciation: ' fi-l ə r
Function: noun
Date: 15th century
: one that fills: as a : a substance added to a product (as to increase bulk, weight, viscosity, opacity, or strength) b : a composition used to fill the pores and grain especially of a wood surface before painting or varnishing c : a piece used to cover or fill in a space between two parts of a structure d : tobacco used to form the core of a cigar e : material used to fill extra space in a column or page of a newspaper or magazine or to increase the size of a work (as a book) f : a pack of paper for a loose-leaf notebook g : a sound, word, or phrase (as “ you know? ” ) used to fill pauses in speaking