Sadly it can’t be added to after the passing of Douglas Adams but his books with John Lloyd “The Meaning of Liff “ which gave place names to experiences/objects in life for which there was no existing word was most useful (and very funny)!
I’m proposing a new one:
Skem: (noun) "the residual amount of cappuccino spume which clings to a coffee cup and which can’t be dislodged even when the cup is inverted and vigorously shaken".
citation: " you spend 3 quid on a mug of milky weak coffee and 10 bob of it ends up as a load skem stook to the bottom of ya cup"
For more on the place.