IV is the Roman numeral that represents the number 4. In the Roman numeral system, letters from the Latin alphabet are used to signify values. The letter "I" stands for 1, and "V" stands for 5. To indicate 4, the numeral is formed by placing "I" before "V," which means one less than five. Roman numerals are often used in various contexts, such as in the naming of monarchs and popes, like Louis IV or Pope IV. They are also commonly found on clock faces, in movie titles, and in the numbering of events, such as the Super Bowl IV.