dB (Decibel)
Definition
A logarithmic unit used to measure the relative intensity of a sound or the level of an audio signal. Because human hearing is logarithmic in nature, decibels reflect how we actually perceive changes in loudness.
In Simple Terms
The unit used to measure how loud something is. A small number change makes a big difference — turning something up by 10 dB makes it sound roughly twice as loud to your ears.
Common Confusion
dB alone is a relative unit and requires a reference point to have absolute meaning — dBFS, dBSPL, dBu, and dBTP all measure different things.