- the ninth letter and third vowel of the modern English alphabet
- any of several speech sounds represented by this letter, in English as in bite or hit
- something shaped like an I
- (in combination): an I-beam
WordReference Random House Learner's Dictionary of American English © 2017
ˈRo•man ˈnu•mer•al,^{}
n. [countable]
WordReference Random House Unabridged Dictionary of American English © 2017- any of the numerals in the ancient Roman system of notation, still used occasionally. The basic symbols are I (=1), V (=5), X (=10), L (=50), C (=100), D (=500), and M (=1000).
Ro′man nu′merals,^{} 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, X̄ 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.
thus, X̄ 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.
- 1725–35
Collins Concise English Dictionary © HarperCollins Publishers::
i, I /aɪ/ n ( pl i's, I's, Is)
i symbol for
- the imaginary number √–1
I /aɪ/ pron
- (subjective) refers to the speaker or writer
I symbol for
- iodine
- current
- isospin
- (Roman numeral) one
See Roman numerals
I. abbreviation for
- International
- Island or Isle