acre-foot
Concise Oxford English Dictionary © 2008 Oxford University Press:
acre-foot
▶noun (pl. acre-feet) a unit of volume equal to the volume of a sheet of water one acre (0.405 hectare) in area and one foot (30.48 cm) in depth; 43,560 cubic feet (1233.5 cubic metres).
'acre-foot' also found in these Oxford entries:

