I was just thinking about this. Why do we call yoyos made from a form of plastic and metal rims bi-metals? Shouldn’t they be called bi-material or metal rimmed yoyos?
Then, yes there are a few bi-metals. The one I can think of is the Catch22. Not sure off the top of my head of any other true bi-metals.
“Bi” doesn’t necessarily refer to two different types of something, very true.
However, when I say “The new Hyundai uses a patented bi-metal construction for the frame.” Most would assume it’s a combination of two different metals.
I guess it doesn’t matter though, since we all know what we mean.
“Bi-metal” makes no sense to me because it sounds like a yoyo made from two different types of metal but I usually say it because it is the first thing I think of to call my Speeder I don’t know why