- The speed of light in vacuum, commonly denoted c, is a universal physical constant that is important in many areas of physics. The speed of light c is exactly equal to 299,792,458 metres per second (approximately 300,000 kilometres per second; 186,000 miles per second; 671 million miles per hour). According to the special theory of relativity, c is the upper limit for the speed at which conventional matter or energy (and thus any signal carrying information) can travel through space.
ADMINISTRATION, n. An ingenious abstraction in politics, designed to receive the kicks and cuffs due to the premier or president. A man of straw, proof against bad-egging and dead-catting.
Ambrose Bierce, The Devil’s Dictionary