# i

Pronunciation: say "Y" /aɪ/

## Pronoun · I

1. Used by the person speaking or writing to refer to themselves as the grammatical subject of a sentence.
   - Simple: Used by a person to talk about themselves as the subject of a sentence.
   - _I know I left the keys somewhere in the kitchen._
   - _Here I am, waiting at the corner as we planned._
5. Used by the speaker or writer to refer to themselves as the grammatical object, after a verb or a preposition. *(nonstandard)*
   - Simple: Used instead of me when a person talks about themselves as the object of a sentence.
   - _Thanks for coming out with Dana and I last night!_
   - _She invited both Marcus and I to the wedding, which surprised everyone._

## Numeral · I

2. The Roman numeral for one, written I or i, used especially in the names of rulers (Napoleon I) and to number items in a list.
   - Simple: The Roman way of writing the number one, as in 'Elizabeth I'.
   - _Napoleon I crowned himself emperor of the French in 1804._
   - _Juan Carlos I gave up the Spanish throne in favor of his son._

## Character

3. The ninth letter of the English alphabet, written in the Latin script and called i.
   - Simple: The ninth letter of the English alphabet, called i.
   - _In many typefaces, a special ligature joins the f to the i so the two letters don't collide._
   - _The company's logo is set in lowercase, with a star in place of the dot on the i._

## Noun · I

4. Short for Interstate, a highway in the US Interstate Highway System, written before the route number, as in I-95. *(US)*
   - Simple: Short for Interstate, a major US highway, written before the road's number, as in I-80.
   - _Construction on I-405 slowed the morning commute to a crawl._
   - _The motel is just off I-70, about an hour west of Denver._
7. Short for independent, a politician or voter who belongs to no political party, as in I-Maine. *(US)* — Abbreviation of independent.
   - Simple: Short for independent, a politician or voter who belongs to no party, as in I-Maine.
   - _Rep. Tom Harlan (I-Colo.) announced Tuesday that he would seek a second term._
   - _On the seating chart, each senator is marked D, R, or I._
10. In metaphysics, the ego: a person's conscious self, the one who thinks and experiences.
   - Simple: The inner self, the part of a person that thinks and is aware.
   - _The poem gives voice to a divided I, torn between duty and desire._
   - _For the philosopher, the I that doubts is the one thing that cannot be doubted._

## Noun

6. The name of the letter I/i of the Latin script.
   - Simple: The name of the letter that is written I or i.
   - _In English, i rhymes with 'my' and 'why,' which surprises many Spanish speakers._
   - _Reciting the alphabet, the children giggled when they reached i, because it sounded like 'eye.'_

## Symbol

8. In mathematics, the imaginary unit: a fixed square root of -1, plotted on the vertical axis of a graph.
   - Simple: In math, a number that gives -1 when it is multiplied by itself.
   - _Every complex number can be written as a real number plus a real multiple of i._
   - _Multiplying by i turns a point on the complex plane a quarter turn counterclockwise around zero._
13. A common variable name for a generic index, especially the counter in a loop.
   - Simple: A letter often used in math and computer programs as a counter, especially for steps that repeat.
   - _The loop keeps running while i is less than the length of the list._
   - _In the formula, i runs from 1 to n, picking out each measurement in turn._

## Symbol · I

9. In chemistry, the symbol for the element iodine.
   - Simple: The symbol scientists use for the chemical element iodine.
   - _Among the halogens, I sits below Br and above At._
   - _In the formula for potassium iodide, K and I appear in a one-to-one ratio._
11. In inorganic chemistry, the Roman numeral that specifies an oxidation state of +1.
   - Simple: In chemistry, a sign showing that an atom's oxidation state is plus one.
   - _The chemist reduced the copper(II) solution until only copper(I) ions remained._
   - _Mercury(I) compounds contain pairs of mercury atoms bonded to each other._
14. In physics and electronics, the symbol for electric current, usually measured in amperes.
   - Simple: A symbol for electric current in science and engineering.
   - _Divide the voltage by the resistance to find I._
   - _The datasheet lists the maximum I the part can carry without overheating._
15. In linear algebra, the symbol for the identity matrix.
   - Simple: In math, a symbol for the identity matrix, a special grid of numbers.
   - _Eigenvalues are found by setting the determinant of A minus λ times I equal to zero._
   - _The program checks its work by confirming that the matrix times its inverse gives I._
16. In physics, the symbol for moment of inertia.
   - Simple: In physics, a symbol for how hard it is to change the way an object spins.
   - _Torque equals I times angular acceleration, just as force equals mass times acceleration._
   - _The engineers lowered I by moving the flywheel's mass closer to its axle._

## Numeral

12. Letter form of the ordinal ninth. — The ordinal number ninth, derived from this letter of the English alphabet, called i and written in the Latin script.
   - Simple: Letter form of ninth. It marks the ninth thing in a list labeled a, b, c, and so on.
   - _Paragraph 4(i) comes right after 4(h) and sets out the late fee._
   - _On the answer sheet, she circled (i), the last of the nine choices._

## Interjection · I

17. Obsolete spelling of aye: yes, used to agree or to vote in favor of something. *(obsolete)* — Obsolete spelling of aye.
   - Simple: Obsolete spelling of aye: yes. Old writers sometimes wrote I where we now write aye.

## Other meanings

- (noun) Short for instruction, in computing, a single basic operation that a processor carries out, as in I-cache.
- (noun) Short for instrumental case: the grammatical case that marks the means or tool by which an action is done, used as a label in grammar tables.
- (symbol) In physics, the symbol for isotopic spin.

## Origin

**Meanings 9, 11, 14–16** — From Latin I, which came through Etruscan and Greek iota (Ι) from the Phoenician letter yod (𐤉), which may in turn go back to an Egyptian hieroglyph showing an arm.
**Meanings 8, 13** — In mathematics, i for the imaginary unit is an abbreviation of imaginary; in engineering, i for electric current abbreviates the French intensité du courant, first used by André-Marie Ampère. In computer programming, i as a generic index abbreviates index, and in linguistics it abbreviates identity.
**Meanings 1, 5, 10** — From Middle English I (also ik, ich), from Old English ic, from Proto-Germanic *ik, *ek and ultimately Proto-Indo-European *eǵh₂óm ("I"). German ich and Dutch ik come from the same source.
**Meanings 4, 7** — An abbreviation: in these uses I stands for a word that begins with it, such as Interstate, instrumental, instruction or independent.
**Meaning 2** — From the Roman numeral I for one, which is thought to come from a tally mark, a single stroke or notch made when counting; i is its lowercase form.
**Meanings 3, 6, 12** — From Latin i, the lowercase form of the letter I.

Source: DictionaryAI, https://dictionaryai.com/define/i (written from Wiktionary data, CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/).