The speed of information being transmitted across a serial interface, expressed in units of bits per second (bps). For example, a baud rate of 9600 refers to bits being transmitted (or received) from one piece of equipment to another at a rate of 9600 bps. Thus, a seven bit ASCII character plus parity bit plus one stop bit (total nine bits) would be transmitted in 9/9600 sec. = 0.94 ms or about 1000 characters/sec. When communicating via a serial interface, the baud rate settings for two pieces of equipment must match.
The term was derived from the name of J.M.E. Baudot, a French pioneer in the field of printing telegraphy.