Roman numeral

American  

noun

1. one of the numerals in the ancient Roman system of notation, still used for certain limited purposes, as in some pagination, dates on buildings, etc. The common basic symbols are I (=1), V (=5), X (=10), L (=50), C (=100), D (=500), and M (=1000). The Roman numerals for one to nine are: I, II, III, IV, V, VI, VII, VIII, IX. A bar over a letter multiplies it by 1000; thus, X̅ equals 10,000. Integers are written according to these two rules: If a letter is immediately followed by one of equal or lesser value, the two values are added; thus, XX equals 20, XV equals 15, VI equals 6. If a letter is immediately followed by one of greater value, the first is subtracted from the second; thus, IV equals 4, XL equals 40, CM equals 900. Examples: XLVII(=47), CXVI(=116), MCXX(=1120), MCMXIV(=1914). Roman numerals may be written in lowercase letters, though they appear more commonly in capitals.

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Etymology

Origin of Roman numeral

First recorded in 1725–35

Example Sentences

The Saudi-backed circuit, whose name is derived from the Roman numeral for '54', had previously touted its three-round tournaments as a core distinction from traditional golf events.

From Barron's • Nov. 4, 2025

It can come off a little pretentious, with its Roman numeral “chapter” titles, nervous zoom shots and ponderous voice-overs.

From Los Angeles Times • Oct. 10, 2024

“I had a great meeting with President Roman numeral 11,” Day said.

From New York Times • Nov. 19, 2023

U.S. captain Davis Love III was asked if he felt bad for Trevor Immelman, who was chosen International captain long before LIV was anything more than a Roman numeral.

From Seattle Times • Sep. 19, 2022

The door was interesting, much more complicated than the Roman numeral combination lock above.

From "The Mark of Athena" by Rick Riordan