Backfill is the process of replacing soil or other material into a hole or trench that has been excavated. Synonyms for backfill include infill, refill, pack, replace, refill, and cover. Infill refers to filling a space or area with soil or other materials to make it level. Refill means filling a hole that was previously excavated. Packing is the process of compacting soil, gravel or material to create a stable foundation. Replace refers to replacing an excavated material with a similar substance. Cover describes the act of placing a layer of material over a surface or area. Each synonym for backfill is used in different circumstances and offers a unique purpose in construction or excavation.