backfill

American  

[bak-fil] / ˈbækˌfɪl /

noun

1. material used for refilling an excavation.

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verb (used with object)

1. to refill (an excavation).

2. to make up for a loss or shortfall of supplies or funds.

   It is illegal to backfill the state budget with federal emergency funds.

3. to fill (a recently vacated position), often with an internal candidate or temp.

backfill British  

/ ˈbækˌfɪl /

verb

1. (tr) to refill an excavated trench, esp (in archaeology) at the end of an investigation

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noun

1. the soil used to do this

Etymology

Origin of backfill

First recorded in 1950–55; back ² + fill

Example Sentences

If there is a shortfall, there’s about $840 billion in revenue from businesses—entities without claims to clean consciences—raised through customs and corporate income taxes that could be used as morally inert backfill.

From Slate • May 11, 2026

It’s too early to say how California refineries — the state’s main crude oil importers — plan to backfill the loss of Persian Gulf oil.

From Los Angeles Times • May 3, 2026

“Frontier, JetBlue, and United all made concerted efforts to backfill Spirit’s markets out of Florida” after Spirit filed its second bankruptcy in September, the analyst continued.

From Barron's • May 1, 2026

Shaun Keaveny, host of The Rock Show, will backfill the slot until the end of March.

From BBC • Mar. 12, 2026

“It’ll be a balance of tech and human, but what it’s not is ‘Let’s just take a bunch of people out and see if we can backfill with AI,’” Grady said.

From The Wall Street Journal • Nov. 6, 2025