Bit depth in audio refers to the number of bits used to represent the amplitude of each sample in a digital audio file. In other words, it determines the resolution of the audio signal.The bit depth is usually expressed in bits per sample, and common values are 16 bits, 24 bits, and 32 bits. The higher the bit depth, the greater the dynamic range of the audio signal and the more accurately it can be represented. For example, with a bit depth of 16 bits, the audio signal can be represented by 65,536 discrete amplitude levels, while with a bit depth of 24 bits, the audio signal can be represented by 16,777,216 discrete amplitude levels. Having a higher bit depth can lead to a higher signal-to-noise ratio and less distortion in the audio signal.