The rate at which data is transferred to and from a device. Normally expressed in bits/second rather than bytes/second e.g. kilobits or megabits per second.
The rate at which data can be transferred, usually expressed as Kilobits per second (Kbps) or bytes per second (Bps)
the number of megabytes of data that can be transferred from the read/write heads to the disk controller in one second. 
The rate at which data can be transferred, usually expressed as Kilobits per second (Kbps) or bytes per second (Bps). 
The rate at which data is transferred from one device to another, usually expressed in bit per second or in bytes per second.