Definition of "mega-" in English

prefix

1. (originally) Very large, great.

2. In the International System of Units and other metric systems of units, multiplying the unit to which it is attached by one million (10⁶).

   • Near-synonyms: million, M

3. (computing) Multiplying the unit to which it is attached by 2²⁰ (= 1,048,576, the binary number closest to a million). Computing symbol: Mi.

4. (computing, marketing) Multiplying the unit to which it is attached by 2¹⁰ × 10³ (= 1,024,000, the binary round number closest to a million).

5. (slang, augmentative) Really, very, uber-, super-.