When referring to an electrical circuit or or energy generation system, load is the the amount of power delivered (or deliverable) along the entire circuit or between specific points on the system. In this context, load for a residential bathroom circuit at a given moment might be 850 watts, consisting of 800 watts for a hair dryer and 50 watts for a light bulb.

Load is also used in the energy industry as the moment-to-moment measurement of power requirement in the entire system. For example, midday load for a given area of town might be 0.5 megawatts. In this context, load is the real measurement of customer demand for energy. It can also be used to refer to demand over a given period of time, rather demand at a single moment in time. The industry usually refers to load in three contexts: industrial load, commercial load and residential load.

Load can also refer to any electrical device consuming energy in a circuit. For example, a single household is a load on the municipal distribution system, a switched-on clock radio is a load on a household circuit, the amplifier circuit within the radio is a load on the radio's circuitry, and a transistor or chip within that circuit is a load on the amplifier circuit.

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