Definition: Heavy rain.
Origin
So many pig players wrote that this phrase originated in the Middle Ages when cats and dogs slept on thatched roofs of cottages and fell onto unsuspecting sleeping occupants during heavy downpours, that I started to wonder if this was the case. Although I did not run across this explanation, there seems to be a number of theories. One theory claims that the sound of thunder during a heavy rain was reminiscent of the cacophony created by fighting cats and dogs. Another suggests that this expression can be traced all the way back to ancient mythology when cats symbolized rain and dogs represented wind. The one I like best, however, blames the origin on the bubonic plague of the 14th century. It seems not only people were afflicted with this horrific disease, but cats and dogs as well. During heavy rainfalls the remains of hundreds of cats and dogs would be washed out into the streets. Honorable mention goes to Jack Huber for his inventive story about kings, queens and incest.
