Today's Word of the Day means...
"High-speed computer stores 2.5 megabits" [headline in "Electronics" magazine, Oct. 1, 1957]
One million (106): megahertz.
Much: I got mega homework tonightadverb
Very: This dude is mega gross (1980s+ Students & teenagers)
A very large specimen, quantity, etc, of what is indicated: megabitch/ megablitz/ mega-cost/ megafame/ megagreed/ megahopes/ megamodel/ mega-travel (1981+)