Mains is the general purpose alternating current (AC) electrical power supply (as in "I've connecte the appliance to the mains"). The term is not often used in the United States and Canada. In the US, mains power has a variety of names. These include household power, household electricity, domestic power, wall power, line power, AC power, city power, and grid power. In Canada, it is sometimes called hydro, because much of the Canadian electrical generating capacity is hydroelectric.