Prefix · one million / enormously large
Signals one million units or enormous size: megabyte, megawatt, megapixel, megacity.
Written by Bryan López, English teacher · Updated
Mega- comes from Greek "megas" (great, large) and in the International System of Units (SI) means exactly one million (10⁶): megabyte = one million bytes; megawatt = one million watts; megahertz = one million hertz. It is the SI power prefix that follows kilo- (thousand) and precedes giga- (one billion) on the scale.
In informal language, mega- signals enormous size or importance without implying exactly one million: megastar, megacity (a city of more than ten million people), mega-event. In this informal use, mega- simply means "very large" or "extremely important," much like super- or ultra-.
Attaches to units of measurement (no hyphen) and informal nouns (sometimes hyphenated):
Pronunciation: /ˈmeɡə/, with a hard "g" as in "get." Identical in Spanish and English.
mega-/ˈmeɡə/
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One megabyte (MB) contains 8 megabits (Mb). Internet speeds are measured in megabits per second (Mbps), while file sizes are measured in megabytes (MB). The scale difference between them is a factor of eight.
In the SI, mega- = precisely 10⁶. In everyday speech, "megastar" or "megacity" simply convey enormous scale without a precise mathematical value.
A trick to remember it
Mega- = "one million of" in science (megabyte = 1,000,000 bytes, megawatt = 1,000,000 watts) and "enormous" in everyday speech (megastar, megacity). It sits between kilo- (× 1,000) and giga- (× 1,000,000,000) on the SI scale.
Exercise 1 · Form the word
Exercise 2 · Pick the right one
What is the difference between a megabyte and a megabit?
Exercise 3 · Pick the right one
"Tokyo, with over thirty million people, is often cited as the world's largest ___."
The prefix mega- signals one million units or enormous size: megabyte, megawatt, megapixel, megacity. In Spanish it usually maps to mega-.
The prefix mega- is pronounced /ˈmeɡə/. For example, "megabyte".
"byte" becomes "megabyte". It is a typical example of the mega- prefix.
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