backfill

noun

1. material used for refilling an excavation.

verb (used with object)

2. to refill (an excavation).

verb

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

noun

2. the soil used to do this

n.

1901 (as backfilling), from back (adj.) + fill (n.). The verb was in use by 1930.