I'm interested in tracing the history of the word "Optical Illusion." See these two questions History of optics and https://english.stackexchange.com/q/260495/129806
It seems Greek and Latin words were mixed together to make new words / ideas. Optical Illusion is one: television is another.
Why were words mixed together? Why not keep the words in the same language? It appears Greek has a separate word for "optical illusion;" ophtalmarati. Why was this renamed?