The term 'roman numeral' has many antonyms depending on the context of usage. Some antonyms might include Arabic numerals, Hindu-Arabic numerals, decimal numbers, or just plain numbers. Roman numerals are characters used to represent numbers in ancient Roman numbering systems, while Arabic numerals are the modern system used universally today for representing numbers. Hindu-Arabic numerals, also known as decimal numbers, are the ten digits (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) that form the basis of the decimal system of numbers. In different settings, the antonym of "roman numeral" may differ, depending on the context and usage of the term.