DCXVIII is a Roman numeral that represents the number 618. In the Roman numeral system, "D" stands for 500, "C" for 100, "X" for 10, "V" for 5, and "III" for 3. When combined, these symbols add up to 618. Roman numerals are often used in various contexts, such as in the naming of monarchs and popes, or to denote the year of publication in books. The numeral system originated in ancient Rome and has been used for centuries, although it has largely been replaced by the more common Arabic numeral system in modern times.