We use this term in English to describe heavy rain. While the exact origin of the phrase is unknown, there are lots of possible explanations. One theory is that during a particularly bad storm, small animals such as cats and dogs were sucked into the sky, and then came down in the rain. Another theory says that pets used to huddle together under thatched roofs during storms, and would slip in heavy rain and fall. Yet another theory, which may be more plausible, says that in Victorian times small animals would drown during heavy storms. The phrase makes reference to the bodies of these animals that were carried along the streets by the rain.
While it has never been proven that it actually did rain cats and dogs, there is a meteorological phenomenon called “rain of animals”, where small creatures such as fish and frogs are sucked up into the sky and rained elsewhere.
And finally, don’t confuse “it’s raining cats and dogs” with “fight like cat and dog”. That’s another kettle of fish altogether!
Why do you say “sleep well” and not “sleep good”?
This is a great question. It’s the same as asking why do we say “I speak English well”, and not “I speak English good”. The reason is simple: well is an adverb, and so describes a verb. In the sentence “sleep well”, sleep is a verb in the imperative mood. Good is an adjective, so describes a noun.
We can say “I speak English well” because well is describing the verb speak. We can also say “I speak good English” because good is describing a noun, which in this case is English.
