Definition:
WiMAX is a wireless communications standard designed for creating metropolitan area networks (MANs). It is similar to the Wi-Fi standard, but supports a far greater range of coverage. While a Wi-Fi signal can cover a radius of several hundred feet, a fixed WiMAX station can cover a range of up to 30 miles. Mobile WiMAX stations can broadcast up to 10 miles.
Further Reading:
Book: Playing to win by A. G. Lafley and Roger L. Martin