Etymology
Advertisement
mega- 

before vowels meg-, word-forming element often meaning "large, great," but in physics a precise measurement to denote the unit taken a million times (megaton, megawatt, etc.), from Greek megas "great, large, vast, big, high, tall; mighty, important" (fem. megale), from PIE root *meg- "great." Mega began to be used alone as an adjective by 1982.

High-speed computer stores 2.5 megabits [headline in "Electronics" magazine, Oct. 1, 1957]
Related entries & more 
Advertisement
megacity (n.)

also mega-city, "very large city," by 1958, from mega- + city.

Related entries & more 
megawatt (v.)

unit of measure equivalent to one million watts, 1885, from mega- "one million" + watt.

Related entries & more 
Advertisement
megacephalic (adj.)

"having an unusually large head," 1876; see mega- + -cephalic.

Related entries & more 
megahertz (n.)

"one million Hertz," 1941, from mega- + Hertz.

Related entries & more 
megavolt (n.)

unit of measure equivalent to one million volts, 1868, from mega- "one million" + volt.

Related entries & more 
megaton (n.)

unit of explosive power equal to one million tons of TNT, 1952, from mega- "million" + ton. Related: Megatonnage.

Related entries & more 
megacycle (n.)

"one million cycles" (of oscillation), 1928, from mega- + cycle (n.). Often meaning "one million cycles per second."

Related entries & more