backfillEnglishOxford New American Dictionarybackfill /ˈbakfil, ˈbækfɪl / ▸ verb [with object] refill (an excavated hole) with the material dug out of it: they backfill the hole to street level. ▸ noun material used for backfilling: archaeologists are attempting to understand the origin of the backfill found there.