I did not know this. Did you?
Etymology is cool.
In printing, a cliché was a printing plate cast from movable type. This is also called a stereotype.When letters were set one at a time, it made sense to cast a phrase used repeatedly as a single slug of metal. “Cliché” came to mean such a ready-made phrase. The French word “cliché” comes from the sound made when the matrix is dropped into molten metal to make a printing plate.