It’s a condition where 2 or more of the senses are joined together by the brain. So for instance someone might associate colours with numbers, or tastes with letters, or smells with sounds.
I experience emotions as colours. So if someone asks me to describe how something feels, my first reaction is to describe it in colours, so for instance a hug is rich chestnut brown in the centre, surrounded by orange that radiates out into yellow then white – then I have to think how to convert that so that another person would understand it.
I also experience tastes as colours, which can lead to interesting descriptions of what something tastes like when my other half is cooking and asks me to taste something and tell him what it needs…blank looks when I tell him it’s not green enough! :lol: