Roman numeral

American  

noun

Roman numerals plural

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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Other Word Forms

Noun Inflected Forms

• Roman numerals
  plural

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

According to the source, he also told investigators his tattoo included the Roman numeral 58 to indicate he was the 58th deputy inked with that image.

From Los Angeles Times • Jan. 11, 2024

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

From New York Times • Nov. 19, 2023

King Carl Gustaf uses the Roman numeral XVI to show that he is the 16th king named Carl to reign in Sweden.

From Seattle Times • Sep. 14, 2023

So was I, the Roman numeral for one, except for the crossbars on top and bottom.

From "Uglies" by Scott Westerfeld