In many audio applications one can find a waveform representation, but the y-axis normally is never labelled. 

**Now, if you would plot your own waveform and wanted to label it, what would be a correct label for the y-axis?** 

For me the y-axis represents vibrations, but for "vibration" or "relative vibration" as label sounds strange, I am also not 100% sure, if vibration is the correct term. Thank you for any hint!

![enter image description here](https://i.stack.imgur.com/NUjHm.png)