A Clowder of Cats - A group of kittens is called a litter but a group of adult cats its called a clowder or sometimes even a glaring. Why anyone would choose to call a group of cats a glaring is completely beyond us! When we see a group of cats, the last thing we do is glare! They're purrfect! Source: The Oxford Dictionary
There's a type of word in the English language called a "collective noun." It is a word used for a group of individuals. What is a group of cats called? It's called a clowder! A clowder of cats. Read more funny #cat facts here!
The correct term for referring to a group of cats is 'clowder'. Interestingly, there are also two other valid ways to refer to a group of cats, other than just saying "group of cats" or "cats". Those other two terms are 'clutter' and 'glaring'. In addition to this, if one wants to refer to a group of wild cats, the correct terms are 'dowt' and 'destruction'. A male cat, when neutered, is called a "gib", when not, is called a "tom". Female cats are known as "molly".