Baud

A unit of transmission speed that measures the number of distinct symbol changes (signalling events) made to the transmission medium per second in a digitally modulated signal.

The term "baud rate" is commonly used to mean bit rate; this usage is incorrect, as 1 symbol can carry more than 1 bit of information. For example, in voiceband modems, it is common for 1 symbol to carry 3 or more bits.