Definition: The word "Casio" refers to a company, brand, or product that specializes in high-end digital watches. It is a Japanese watch manufacturer known for its precision, durability, and functionality. The word "casio" itself is a combination of two Japanese words, "clock," which means timepiece, and "saigo," meaning the word "time." Therefore, it refers to a type of watch with a rotating or sliding case that allows for accurate timekeeping.