What is the meaning of Mega-?

Used with taxon names to form other taxon names, usually for a morphologically similar taxon differing only in size

Very large, great.

In the International System of Units and other metric systems of units, multiplying the unit to which it is attached by one million (10.) SI Symbol: M.

Multiplying the unit to which it is attached by 2 (= 1,048,576, the binary number closest to a million). Computing symbol: Mi.

Multiplying the unit to which it is attached by 2 × 10 (= 1,024,000, the binary round number closest to a million).

mega- (SI system)

mega- (in the International System of Units and other metric systems of units, multiplying the unit to which it is attached by one million (10.))

mega- (all senses)

mega- (very large, great)

mega- (multiplication factor of one million)

Source: wiktionary.org

See also