What is the definition of symbol rate in a digital transmission?

Symbol rate, commonly known as baud rate, refers strictly to the number of times the physical waveform changes per second to convey information. Depending on the modulation scheme being used, a single change in the waveform (a symbol) can represent one or more bits of data. It is important to distinguish symbol rate from bit rate. While bit rate measures the actual number of data bits transferred per second, symbol rate only measures the signaling events. Therefore, options suggesting the number of characters per second or error correction rates describe data processing metrics rather than the physical waveform changes.