I have always known pots to either have an audio or a linear taper.
I'm looking at a schematic which has numerous pots. Some say they are "W
taper", the others say they are "K Taper". I have not seen them listed
in this way, ever.

What do these letters mean?
Are there other letters used?

Anyone have a chart that shows and explains them?

Thanks

(This schematic is for an early 1990's era semiconductor preamp, using
op-amps, and transistors).