Fun connections.

"Stereotype" is a printer's term. Moveable type is expensive. You don't want to keep it tied up longer than needed, so you make a mould from the set type and cast a plate from that.

The "stereotype" is the mould.

A "cliché" is what the French called plate made from that mould, it's onomatopoeia from the sound of removing the plate from the mould.

"Boilerplate" is widely repeated text from the round stereotype castings of newspaper columns ready to throw on a drum press.