A megahertz is one million (or 106) hertz.
See hertz, kilohertz (one thousand hertz), gigahertz[?] (109 hertz), terahertz[?] (1012 hertz), and petahertz[?] (1015 hertz).
... of tapes of their shows, as long as no profits were made on the sale of their show tapes. Starting in 1991 the Grateful Dead has released numerous live concerts from ...