backfill /ˈbækfɪl/verb 5noun 4forms 3 verb5 •To refill a hole with the material dug out of it. •To refill an excavation unit to restore the former ground surface and/or to preserve the unit and make it recognizable as having been excavated.We backfilled the cistern with pea gravel to discourage its use as a refuse container. •To replenish or restock due to attrition or loss.The company backfilled Joe's position after he was terminated. •To enter an online game that's already in progress, replacing a player who left early. •(US) To provide reserve support. noun4 •The material that has been used to refill an excavation. •(US) Reserve support personnel. •(US) That which backfills; a replacement. •Material in a story set earlier in the past, providing history or context for the current action. formsbackfilled · backfilling · backfills