Q & A on The definition of "mega" Q: My question is about the prefix "mega", as in the phrase "2 megabytes per second". mega is well established in the sciences and mathematics as meaning 10^6. However, computer scientists seem to use it to refer to powers of two. In your book should mega be interpreted to be 10^6 or 2^20 (i.e., 1024x1024)? A: In the Computer Science and the computer industry, "mega" is almost uniformly defined to be 1024*Kilo or 1024*1024 = 2^20. That's the definition used in my books.