The Roman numeral "DCLXXXV" represents the number 685. In this numeral, "D" stands for 500, "C" for 100, "L" for 50, and "X" for 10. The combination of these symbols adds up to 685, as there are three "X" symbols (30), one "L" (50), one "C" (100), and one "D" (500). Roman numerals are a numeral system originating from ancient Rome. They use combinations of letters from the Latin alphabet. This system was widely used throughout the Roman Empire and is still seen today in various contexts, such as clock faces and book chapters.