I've heard that the cat which there may not be enough room to swing actually refers to a type of whip. Is that true? What is the actual origin of the phrase not/barely enough room to swing a cat?
Personally, I know two explanations. The first is provided by Phrase Finder:
However, as the post says, there is a possibility that this explanation is not true, if the cat-o'-nine-tails was invented after the phrase was invented.
The second explanation, which comes from my personal reading, is a veterinary practise.
I read, in James Herriot's accounts of his life as a veterinary in 1950s, that it seems that when trying to resuscitate a cat, or a dog, the vet would take the cat by the hind legs, and swing the cat around and around. This came from his book, Vets might fly, if my memory serves me correctly. The phrase could possibly have evolved from this practise. That is another possible explanation.
The American Heritage dictionary of idioms writes:
This section in Origins of the Specious: Myths and Misconceptions of the English Language recognizes that the above is the typical story, but argues that the phrase is in fact earlier:
So the "cat" may have originally been a literal cat, which in Elizabethan times was used as a toy. However, more sources like to report that the phrase really does refer to a whip. Either way, the phrase seems to be earlier than the American Heritage Dictionary reports.