Peak Meter
Definition
A meter that displays the instantaneous maximum level of an audio signal. Essential for preventing clipping but a poor indicator of perceived loudness.
In Simple Terms
The meter in your DAW that shows the loudest instant of your audio. Useful for avoiding clipping, but it doesn't tell you how loud your track actually sounds. For that, you need a LUFS meter.
In Practice
A peak meter shows a snare hit reaching -3 dBFS, confirming it will not clip, but the engineer uses a separate LUFS meter to assess overall mix loudness.