Optimus means “the best” in Greek. It’s the root word of common ones in our culture, like, “optimize,” and, “optimism.” 

Optimize: The “-ize” in “optimize” means “to make,” so the whole word means “to make the best.”

Optimism: The “-ism” in “optimism” means “taking side with,” or “imitation of,” so the whole word means “to take side with (or to imitate) the best.”