Megabit

(Comp Sci.)
Equal to 1,048,576 bits, though commonly referred to as one million bits. Abbreviated as mb.

mB = Megabyte
mb = Megabit
Examples:

mBps (Megabytes Per Second)
mbps (Megabits Per Second)

I downloaded at 6mbps.
Which is approximately 6,291,456 bits.

by VoiDeD May 01, 2005