Named after Gordon E. Moore (born 1929), co-founder of Intel. In its current form, it states that the power of integrated circuits doubles every 18 months for the same component costs.
In a paper published in 1965 Moore pointed out that "the complexity for minimum component costs has increased at a rate of roughly a factor of two per year". Later on, the doubling time was revised to 18 months and the observation was extended from the number of transistors that could be "[crammed] onto integrated circuits" further to memory capacity, processing speed, pixel resolution and the full computing performance.
Constant doubling time is a feature of exponential functions. This means that power grows exponentially, and cost decays exponentially. Accordingly, every 10 years, integrated circuit power grows 100 times, and cost shrinks to 1/100th.
Moore's law helps explain the pervasiveness of electronic circuitry and the omnipresence of computers in nowadays life.