watt The unit of electrical power, defined as the power dissipated by 1 ampere of current flowing through 1 ohm of resistance.

wavelength The distance between successive cycles of a periodic wave.

widescreen A video display or projected image with an aspect ratio wider than 1.33. Widescreen TV shave an aspect ratio of 1.78, also expressed as “16:9.”

windowbox A video image that results from displaying an image of standard (1.33) aspect ratio on a television set of widescreen (1.78) aspect ratio. The picture is presented between black bars to the left and right sides of the image. Contrast with “letterbox.”