The megawatt (symbol: MW) is a unit for measuring power equal to one million (106) watts.
The productive capacity of electrical generators operated by utility companies is often measured in MW. Few things can sustain the transfer or consumption of energy on this scale; some of these events or entities include: lightning strikes, naval craft (such as aircraft carriers and submarines), engineering hardware, and some scientific research equipment (such as the supercollider and large lasers).
For reference, about 10,000 100-watt lightbulbs or 2,000 computer systems would be needed to draw 1 megawatt. Also, 1 MW equals approximately 1341 Horsepower. Modern high-powered diesel-electric railroad locomotives typically have a peak power output of 3–5 MW, whereas a typical modern nuclear power plant produces on the order of 500–2000 MW peak output.
According to the Oxford English Dictionary, the earliest citing for "megawatt" is a reference in the 1900 Webster's International Dictionary of English Language. The OED also says "megawatt" appeared in a 28 November 1947 article in Science (506:2).