Colourway is a necessary word. It doesn’t describe a colour or replace the word colour, it defines the colours which make up a product (which may of course be a single colour, but may be multiple colours, or even the same colours but in a different pattern).
So the RED colourway may not be all red, and other products that are mainly red too will have a different colourway name to differentiate them.
Sorry – spot the (ex) clothing buyer.
Pain Cave is one that I won’t use – it’s just a garage / shed / spare room with a turbo trainer and a rusty barbell.