a person or thing that fills in, as a substitute, replacement, or insertion: The company used a fill-in for workers on vacation.
a brief, informative summary; a rundown.

Origin of fill-in

First recorded in 1915–20; noun use of verb phrase fill in Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for fill-in

Contemporary Examples of fill-in

  • He guested as a lay preacher on the Hour of Power and dabbled in talk radio as a fill-in for Boortz.

    The Daily Beast logo
    Pizza Guy for President!

    Bryan Curtis

    January 13, 2011

Historical Examples of fill-in

  • The largest number of fill-in wefts occurs roughly at a point about a third up from the end.