1. The electric load on a system, integrated over a specific time interval; usually expressed in watts or kilowatts.
2. The volume of gas per unit time (usually expressed in cubic feet per hour or liters per second) or the amount of heat (usually expressed in Btu per hour or megajoules per hour) required for the operation of one or more gas appliances.
3. The rate of flow of water, usually expressed in gallons per minute (liters per second), furnished by a water supply system to various types of plumbing fixtures and water outlets under normal conditions.