It rains cats and dogs意思是
"It rains cats and dogs" is an English idiom that means it rains very heavily or torrentially. The origin of this expression is unclear, but it is believed to have first appeared in the mid-17th century. One theory is that it may have originated from the old practice of dumping animal carcasses into the streets, which would then be washed away by heavy rains, giving the appearance that it was raining animals. Another theory suggests that the phrase may come from the Dutch expression "het regent katten en honden," which means "it's raining cats and dogs," and may have been brought to England by Dutch traders.