I

UK: 'I', 'i': /ˈaɪ/ US: 'I', 'i': /aɪ/ ,'I', 'i': (ī)

Collins Concise English Dictionary © HarperCollins Publishers::

I / aɪ/ pronoun

1. (subjective) refers to the speaker or writer

Etymology: 12th Century: reduced form of Old English ic; compare Old Saxon ik, Old High German ih, Sanskrit ahám

I symbol

1. iodine
2. current
3. isospin
4. a particular affirmative categorial statement, such as some men are married, often symbolized as SiP
   Compare A, E, O1
5. (Roman numeral) one
   See Roman numerals

abbreviation

1. Italy (international car registration)

WordReference Random House Learner's Dictionary of American English © 2025

I, i /aɪ/   n. [countable] , pl. I's or Is, i's or is. 

1. Linguistics the ninth letter of the English alphabet, a vowel.

I /aɪ/   pron., [nom.] I, poss. my or mine, obj. me;
 pl. [nom.] we, poss. our or ours, obj. us;
 n., pl. I's. 
pron. 

1. (used as the singular subject pronoun by a speaker or writer in referring to himself or herself):
   I'll be happy to see you. Am I glad to see her!

n. [countable]

2. Philosophy the ego;
   the self:
   the "I'' of the narrator.

I,  an abbreviation of:

1. Transport, Pronouns interstate (used with a number to designate an interstate highway):
   I-95.

WordReference Random House Learner's Dictionary of American English © 2025

ˈRo•man ˈnu•mer•al,  n. [countable]

1. 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).

WordReference Random House Unabridged Dictionary of American English © 2025

I, i  (ī), n., pl. I's  or Is, i's  or is. 

1. Linguistics the ninth letter of the English alphabet, a vowel.
2. Linguistics any spoken sound represented by the letter I or i, as in big, nice, or ski.
3. something having the shape of an I.
4. a written or printed representation of the letter I ori. 
5. a device, as a printer's type, for reproducing the letter I ori. 

I  (ī), pron., nom. I, poss. my  or mine, obj. me;
 pl. nom. we, poss. our  or ours, obj. us;
 n., pl. I's. 
pron. 

1. the nominative singular pronoun, used by a speaker in referring to himself or herself.

n. 

2. (used to denote the narrator of a literary work written in the first person singular).
3. Chemistry [Metaphys.] the ego.

• bef. 900; Middle English ik, ich, i; Old English ic, ih; cognate with German ich, Old Norse ek, Latin ego, Greek egó̄, Old Church Slavonic azù, Lithuanian aŝ, Sanskrit ahám

Usage

See me. 

I, 

1. Transport, Pronouns interstate (used with a number to designate an interstate highway):
   I-95.

I,  Symbol.

1. the ninth in order or in a series.
2. (sometimes l.c.) the Roman numeral for 1. Cf. Roman numerals.
3. [Chem.] iodine.
4. Biochemistry isoleucine.
5. [Elect.] current.
6. Philosophy [Logic.] See particular affirmative. 

i, [Math.]

1. Also called imaginary unit. the imaginary number &fullradicoverminus1;
   .
2. a unit vector on the x-axis of a coordinate system.

I, 

1. Symbol, Physics. isotopic spin.

i-, 

1. var. of y-. 

-i-, 

1. the typical ending of the first element of compounds of Latin words, as -o- is of Greek words, but often used in English with a first element of any origin, if the second element is of Latin origin:
   cuneiform; Frenchify.

I., 

1. Independent.
2. Island;
   Islands.
3. Isle;
   Isles.

i., 

1. imperator.
2. incisor.
3. interest.
4. Grammar intransitive.
5. island.
6. isle;
   isles.

WordReference Random House Unabridged Dictionary of American English © 2025

Ro′man nu′merals, 

1. 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.

• 1725–35

Collins Concise English Dictionary © HarperCollins Publishers::

i, I / aɪ/ noun (i's, I's, Is)

1. the ninth letter and third vowel of the modern English alphabet
2. any of several speech sounds represented by this letter, in English as in bite or hit
3. something shaped like an I
4. (in combination): an I-beam

i symbol

1. the imaginary number √–1

Collins Concise English Dictionary © HarperCollins Publishers::

I. abbreviation

1. International
2. Island or Isle