Mbps stands for millions of bits per second or megabits per second and is a measure of bandwidth (the total information flow over a given time) on a telecommunications medium. Depending on the medium and the transmission method, bandwidth is also sometimes measured in the Kbps (thousands of bits or kilobits per second) range or the Gbps (billions of bits or gigabits per second) range.
A megabit is a million binary pulses, or 1,000,000 (that is, 106) pulses (or "bits"). For example, a U.S. phone company T-carrier system line is said to sustain a data rate of 1.544 megabits per second. Megabits per second is usually shortened to Mbps.
Some sources define a megabit to mean 1,048,576 (that is, 220) bits. Although the bit is a unit of the binary number system, bits in data communications are discrete signal pulses and have historically been counted using the decimal number system. For example, 28.8 kilobits per second (Kbps) is 28,800 bits per second. Because of computer architecture and memory address boundaries, bytes are always some multiple or exponent of two. See kilobyte, etc.