A shower is a device that sprays water down on you for washing, and the act of using it. It can also mean a short period of light rain or a large number of things falling or happening at once.
“Shower” comes from Old English “scūr,” meaning a sudden burst of rain. The bathroom sense developed later by likening the falling water to a rain shower. The idea of many small drops coming down together unites all the meanings.
Rain shower, baby shower, meteor shower, and your morning shower all share the same mental picture: lots of small things ‘raining down’ at once. Even a ‘shower of praise’ fits that image. English loves turning weather into metaphors for human life.
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