Candlepower (the antiquated name for candela, cd) was a basic unit of measurement of luminous intensity, first defined in terms of the amount of light produced by a pure spermaceti candle weighing one sixth of a pound, burning at a rate of 120 grams per hour.

In 1960 the 11th Conférence Générale des Poids et Mesures redefined one candela as "the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 X 1012 Hz and that has a radiant intensity in that direction of 1/683 watts per steradian."

Despite being depreciated, flashlight advertisements often describe a product's strength in candlepower.

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