i
/aɪ/ (bre, ipa) · [ˈaɪ] /aɪ/ (ame, ipa) · [ˈaɪ] /ˈī/ (ame, mw)
i — noun
- isingular
- isplural
1. The letter i is the ninth character in English writing. It is a vowel that can s
The letter i is the ninth character in English writing. It is a vowel that can stand for different sounds, as in the words 'win' and 'time'.
The word 'bicycle' is spelled with a lowercase i after the letter c.
lowercase vs capital: letter i is lowercase in most words
Hari wrote a capital I at the beginning of the diary entry.
In class, the teacher asked the students to circle every letter i in the poem.
Camila is learning how to write the letter i in cursive handwriting.
常見錯誤
2. Within the Roman system of writing numbers, the capital letter I is the symbol f
Within the Roman system of writing numbers, the capital letter I is the symbol for one. It appears alongside V, X, and other letters to build numbers from two up to nine.
The Roman numeral I means the number one on the face of this old clock.
Roman numeral I = 1, used on clock faces
David read Chapter I of the book before going to sleep.
World War I ended in 1918 after more than four years of fighting.
On the statue, the year was carved in Roman numerals ending with I for one.
Super Bowl I was played between the Green Bay Packers and the Kansas City Chiefs.
用法筆記
Roman numerals are usually written in capital letters. The lowercase i is not standard for representing numbers in English.
常見錯誤
i — abbreviation
1. used in maps and official documents to show that an area is meant for factories,
used in maps and official documents to show that an area is meant for factories, warehouses, or other types of industry — for example, I-1 for light industrial or I-2 for heavy industrial.
Nia checked the city map and saw that her street was in an I-1 zone.
The planning board voted to change the area from I-2 to residential use.
i + number for industrial zone classification
Only factories and storage buildings can be built on land marked I.
Brandon bought a warehouse in an I district because the rent was lower.
文法句型
i + number
用法筆記
Typically appears as part of a code (I-1, I-2) on zoning maps. Not used in everyday speech.
2. short for the first letter of a person's first name, used when writing someone's
short for the first letter of a person's first name, used when writing someone's name in a formal or shorter style — for example, I. Asimov or J. K. Rowling.
The letter was signed by I. K. Peterson, a lawyer from Chicago.
I. + surname for first initial
Please write your name as last name followed by your first initial.
Kabir wrote "B. Zayd" on the form because the space was too small.
On the old novel's cover, the name 'I. Asimov' appeared in gold above the title.
- initial
the full word, not an abbreviation
文法句型
I. + surname
用法筆記
Always capitalised when used as a name initial. The letter is followed by a period (full stop) in American English.
常見錯誤
3. short for intelligence, most often used as part of the abbreviation I.Q. (intell
short for intelligence, most often used as part of the abbreviation I.Q. (intelligence quotient) to describe a person's measured mental ability compared to others of the same age.
Hugo scored very high on the I.Q. test given by the school psychologist.
The study compared I.Q. scores of children who learned music early.
Amira read that a person's I.Q. can change slightly over many years.
Scientists no longer believe that I.Q. alone decides success in life.
文法句型
I.Q.
用法筆記
Nearly always appears as I.Q. rather than as a standalone 'I' for intelligence. The abbreviation is always capitalised.
4. a symbol used in science and engineering to represent the strength or magnitude
a symbol used in science and engineering to represent the strength or magnitude of something that is being measured — for example, the intensity of light, sound, or a magnetic field. It is not limited to any one specific physical quantity.
The light meter showed an I value of 800 lumens for the brightness in the room.
I as symbol for light intensity measurement
Seoul's noise monitoring station recorded an I level of 82 decibels during the evening rush hour.
I as sound intensity level
When the machine's I reading drops below 20, the technician checks the signal source.
The textbook said I stands for the general intensity of a wave in the experiment.
文法句型
I = value in formulas
用法筆記
The symbol I for intensity is usually written in italics in scientific texts. Do not confuse this general intensity symbol with the letter I used specifically for electric current in circuits.
5. short for interlaced, used in video display standards to show that a screen refr
short for interlaced, used in video display standards to show that a screen refreshes by drawing every other line in each pass rather than every line at once — for example, 1080i or 480i.
The old television broadcast in 1080i, not the newer 1080p format.
number + i for interlaced video format
Diya noticed that 480i video looked less smooth than 720p video.
Most cable channels still send a 1080i signal to customers at home.
A 1080i screen draws 540 lines at a time, but the eye blends them.
- p
progressive scan — draws every line on every pass
文法句型
number + i
用法筆記
Always follows a number (e.g. 1080i, 480i) indicating the vertical resolution. Contrasts with 'p' (progressive scan).
6. short for intransitive, used in dictionaries and grammar books to mark a verb th
short for intransitive, used in dictionaries and grammar books to mark a verb that does not take a direct object — for example, 'sleep (v.i.)' or 'arrive (vi)'.
The dictionary marks "arrive" as v.i. because you cannot arrive something.
v.i. marking intransitive verb
Bao looked up "happen" and saw the label i, meaning no object is needed.
Some verbs like "eat" can be v.t. or v.i. depending on the sentence.
Minh checked the grammar table: v.i. stands for intransitive verb.
- intransitive
the full word, not abbreviated
- v.t.
transitive verb — takes a direct object
文法句型
verb marked i
用法筆記
Often written as v.i. or vi in dictionary entries. Paired with v.t. (transitive verb) as the opposite label.
常見錯誤
7. a written abbreviation for island or isle, used in place names and on maps to sh
a written abbreviation for island or isle, used in place names and on maps to show a piece of land completely surrounded by water
The ferry to I. of Wight leaves the port every two hours.
abbreviation in place names: I. of [Name]
Amira booked a hotel on I. of Man for her summer holiday.
On the map the words 'I. Skye' appeared in small print near the coast.
The sailors watched the cliffs of I. de Ré appear on the horizon.
用法筆記
Often written with a period in British English. Always part of a proper place name, never used alone to mean 'island' in general prose.
常見錯誤
8. the symbol for electric current, used in physics and electronics to show the flo
the symbol for electric current, used in physics and electronics to show the flow of electric charge through a conductor, measured in amperes
In the equation V equals I times R, the I stands for electric current.
I in the formula V = IR (Ohm's law)
Renata measured I at two amperes when she closed the switch.
I measured in amperes (A)
A higher I value means more charge flows through the wire each second.
The circuit diagram had 'I equals 0.5 A' written next to the resistor.
用法筆記
Always written without a period in scientific and mathematical contexts. Used in formulas alongside units such as A (amperes) or mA (milliamperes).
9. a written abbreviation for Indian, used before the names of organizations, gover
a written abbreviation for Indian, used before the names of organizations, government bodies, and institutions to show they belong to or come from India
The I. Space Research Organisation launched a satellite to study the moon.
I. stands for Indian before organization names
Owen read about the I. Navy's rescue mission in the newspaper.
The I. Railways network is one of the largest in the world.
Zayd's mother booked a ticket on I. Airlines for her trip to Chennai.
用法筆記
Most often seen in news headlines, official names of Indian institutions, and on airline or railway branding. Do not confuse this abbreviation with the pronoun 'I'.
常見錯誤
10. a written abbreviation for interstate, used in US road names before a number to
a written abbreviation for interstate, used in US road names before a number to show a major highway that connects different states
Take I. 95 north if you want to drive from New York to Boston.
I. + highway number for US interstate routes
Kevin said the traffic on I. 5 was terrible during the holiday weekend.
A truck broke down on I. 40 near the Arizona border this morning.
The map showed I. 10 running all the way from California to Florida.
用法筆記
Always followed by a number. Only used in American English contexts. In speech, 'I-95' is read as 'eye ninety-five'.
常見錯誤
11. a written abbreviation for Israeli, used before the names of organizations, gove
a written abbreviation for Israeli, used before the names of organizations, government bodies, and official institutions related to the country of Israel
The I. embassy in Paris released a statement about the festival.
I. stands for Israeli before official organizations
Andrei met with the I. ambassador to discuss trade agreements.
The I. shekel has gained value against the dollar this year.
Hiro read about the I. military's new training programme online.
用法筆記
Most often seen in news headlines, diplomatic contexts, and official names of Israeli institutions. In formal writing, the full word 'Israeli' is usually preferred.
i — pronoun
1. You use this word when talking about yourself, before a verb, to show that you a
You use this word when talking about yourself, before a verb, to show that you are the person who does something or who feels a certain way.
I am a teacher at the local primary school near the river.
I + be + [role]: introducing yourself
I always take the bus to work because I do not own a car.
I + verb + reason clause: daily routine
Before class I prefer tea over coffee in the morning.
Last summer I visited my cousin Quan in Tokyo for ten days.
I hope to learn how to play the guitar later this year.
- you
second person singular pronoun — refers to the person being spoken to
文法句型
I + verb (always the subject)
用法筆記
Always written as a capital letter 'I' in English, even when it appears in the middle of a sentence. This is the only English pronoun that is capitalised regardless of position.
常見錯誤
i — symbol
1. In mathematics, the symbol that represents the square root of negative one, writ
In mathematics, the symbol that represents the square root of negative one, written as i, which makes it possible to express numbers that combine a real part and an imaginary part.
In algebra class, Ms. Chen's students learned that i squared equals negative one.
core identity: i² = −1
A number written as 3 + 2i is called a complex number in mathematics.
usage pattern: a + bi form of complex numbers
Without the number i, the equation x² = −1 would have no possible solution.
Electrical engineers use the letter j instead of i to represent √−1.
The value of i appears when solving quadratic equations that have no real roots.
用法筆記
In mathematics, i is always written in lowercase italic. In electrical engineering, j is used instead of i to avoid confusion with electric current (symbol I).
常見錯誤
2. The chemical symbol for iodine, a dark purple non-metallic element that is used
The chemical symbol for iodine, a dark purple non-metallic element that is used in antiseptics and is essential for the human body to function properly.
The periodic table shows I as the symbol for the element iodine.
chemistry context: I on the periodic table
A lack of iodine, marked by the symbol I, can harm the thyroid gland.
In the chemistry lab, Amira wrote the formula I₂ to represent iodine gas.
The symbol I appears on bottles of antiseptic that contain iodine.
Table salt often has added iodine, known by its chemical symbol I.
用法筆記
I is always capitalised when used as a chemical symbol. The element iodine is essential for the production of thyroid hormones.