The unit of measurement of audio level. Ten times the logarithm of the ratio of two power levels. Twenty times the logarithm of the ratio of two voltages. Standard abbreviations using decibels include: dBV (decibels relative to 1 volt), dBu (decibels relative to 0.775 volt), dBm (decibels relative to 1 milliwatt) and dBA (decibels, A weighted).
DECIBEL
Meaning of DECIBEL in English
Guitar English glossary. Английский словарь гитарных терминов . 2012