- (US) Reserve support personnel.
- The material that has been used to refill an excavation.
- (literature) Material in a story set earlier in the past, providing history or context for the current action.
- (US) That which backfills; a replacement.
- (archaeology) 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.
- To refill a hole with the material dug out of it.
- (US) To replenish or restock due to attrition or loss.
"The company backfilled Joe's position after he was terminated."
- (US) To provide reserve support.