Back in the days of 35mm film, a 50mm prime was considered a 'standard' lens. That's because it gives pretty much the same perspective as viewing a scene with the human eye, without the magnification of a telephoto lens or the shrinkage a wide-angle lens uses to squeeze more into the frame.
The flexi disc (also known as a phonosheet or Soundsheet, a trademark) is a phonograph record made of a thin, flexible vinyl sheet with a molded-in spiral stylus groove, and is designed to be playable on a normal phonograph turntable.
Bending, also known as flexure, as used in mechanics. Power cord, or flex, a flexible electrical cable Flex, a flexible cable, as used on electrical appliances. Flex circuit, a flexible printed circuit used in electronic assemblies. Femtosecond Lenticule EXtraction, a form of refractive eye surgery. Flex-fuel, a flexible-fuel vehicle.