"IX" is the Roman numeral for the number 9. It is formed by combining the symbols for 10 (X) and 1 (I), where the smaller numeral is placed before the larger one to indicate subtraction. This numeral system was widely used in ancient Rome and is still seen today in various contexts, such as clock faces and book chapters. In addition to its numerical value, "IX" is also associated with various cultural references. For example, it is the title of the 2019 animated film IX and is often used in video games and literature to denote the ninth installment in a series.