in

1 of 11

preposition

ˈin 

ən,

ᵊn

1

a

—used as a function word to indicate inclusion, location, or position within limits

in the lake

wounded in the leg

in the summer

b

: into sense 1

went in the house

2

—used as a function word to indicate means, medium, or instrumentality

written in pencil

bound in leather

3

a

—used as a function word to indicate limitation, qualification, or circumstance

alike in some respects

left in a hurry

b

: into sense 4a

broke in pieces

4

—used as a function word to indicate purpose

said in reply

5

—used as a function word to indicate the larger member of a ratio

one in six is eligible

in

2 of 11

adverb

ˈin 

1

a(1)

: to or toward the inside especially of a house or other building

come in

(2)

: to or toward some destination or particular place

flew in on the first plane

(3)

: at close quarters : near

play close in

b

: so as to incorporate

mix in the flour

—often used in combination

built-in bookcases

c

: to or at an appropriate place

fit a piece in

2

a

: within a particular place

especially : within the customary place of residence or business

the doctor is in

b

: in the position of participant, insider, or officeholder

—often used with on

in on the joke

c(1)

: on good terms

(2)

: in a specified relation

in bad with the boss

(3)

: in a position of assured or definitive success

d

: in vogue or season

e

of an oil well : in production

f

: in one's presence, possession, or control

after the crops are in

g

: from a condition of indistinguishability to one of clarity

fade in

in

3 of 11

adjective

ˈin 

1

a

: that is located inside or within

the in part

b

: that is in position, operation, or power

the in party

c

: inside sense 2

2

: that is directed or bound inward : incoming

the in train

3

a

: extremely fashionable

the in thing to do

b

: keenly aware of and responsive to what is new and fashionable

the in crowd

in

4 of 11

noun

ˈin 

1

: one who is in office or power or on the inside

a matter of ins versus outs

2

: influence, pull

enjoyed some sort of in with the commandant

—Henriette Roosenburg

in

5 of 11

abbreviation (1)

1

inch

2

inlet

In

6 of 11

symbol

indium

IN

7 of 11

abbreviation (2)

Indiana

in-

8 of 11

prefix (1)

variants or il- or im- or ir-

: not : non-, un-

—usually il- before l

illogical

, im- before b, m, or p

imbalance

immoral

impractical

, ir- before r

irreducible

, and in- before other sounds

inconclusive

in-

9 of 11

prefix (2)

variants or il- or im- or ir-

1

: in : within : into : toward : on

—usually il- before l

illuviation

, im- before b, m, or p

immingle

, ir- before r

irradiance

, and in- before other sounds

infiltrate

2

: en- entry 1

imbrute

imperil

inspirit

-in

10 of 11

noun suffix

1

a

: neutral chemical compound

insulin

b

: enzyme

pancreatin

c

: antibiotic

penicillin

2

: -ine entry 2 sense 1a

epinephrin

3

: pharmaceutical product

niacin

-in

11 of 11

noun combining form

: organized public protest by means of or in favor of : demonstration

teach-in

love-in

Phrases

in for

: certain to experience

in for a rude awakening

Synonyms

Preposition

• by
• per
• through
• via
• with

Adverb

• around
• by
• close
• hard
• near
• nearby
• nigh

Adjective

• à la mode
• a la mode
• au courant
• chic
• cool [slang]
• exclusive
• fashionable
• fresh [slang]
• happening
• hip
• modish
• sharp
• smart
• snappy
• stylish
• supercool
• swell
• swish
• trendy
• voguish

Noun

• authority
• clout
• credit
• heft
• influence
• juice [slang]
• leverage
• pull
• sway
• weight

Examples of in in a Sentence

Preposition

Don't come in here with those muddy feet!

drawn on the wall in crayon

Adverb

She went in and closed the door.

I lost my keys and now I can't get in.

The burglars broke in through the kitchen window.

The pool is deep. Be careful not to fall in.

The boss called us in for a conference.

The fog was closing in fast.

Get your orders in early!

Is the train in yet?

Adjective

the in thing to do

the in place to go

It's what the in crowd is wearing this season.

Noun

When you're trying to get started in show business, it helps to have an in.

They must have an in with the boss.

Recent Examples on the Web

Preposition

An exhibition in Japan highlights supernatural spirits imbued with the fears and anxieties of everyday life. —J.d. Capelouto, semafor.com, 16 June 2025

So we were delayed in getting there because there was just so much damage. —Charlotte Phillipp, People.com, 16 June 2025

Adverb

This conflict risks sucking the US military in, sending oil prices over $100 a barrel, and dragging the US and global economy into recession. —Faisal J. Abbas, semafor.com, 17 June 2025

Plus, big endorsements in the NIL have flowed in fast. —Bruce Feldman, New York Times, 16 June 2025

Adjective

See why 2025 Could Be Intel Stock’s Comeback Year for an in depth look at how Intel stock could be re-rated higher. —Trefis Team, Forbes, 6 Dec. 2024

Optical atomic clocks, accurate to picoseconds, will enable satellite constellations and ground stations to determine satellites’ locations with centimeter-level precision—avoiding potentially catastrophic in-orbit collisions. —Paul Lipman, Forbes, 8 Oct. 2024

Noun

A lot of times, that dictates your ins and your outs. —Mark Olsen, Los Angeles Times, 5 June 2025

This old-fashioned instrument relied on a hand crank, as well as an outside metal canister that contained ice and rock salt to freeze its contents of milk, cream, sugar, and mix-ins. —Joey Skladany, Southern Living, 24 May 2025

Word History

Etymology

Preposition

Middle English, from Old English; akin to Old High German in in, Latin in, Greek en

Prefix (1)

Middle English, from Anglo-French, from Latin; akin to Old English un-

Prefix (2)

Middle English, from Anglo-French, from Latin, from in in, into

Noun suffix

French -ine, from Latin -īna, feminine of -īnus of or belonging to — more at -en

Noun combining form

sit-in

First Known Use

Preposition

before the 12th century, in the meaning defined at sense 1a

Adverb

before the 12th century, in the meaning defined at sense 1a(1)

Adjective

15th century, in the meaning defined at sense 1a

Noun

1741, in the meaning defined at sense 1

Rhymes for in

• been
• bin
• chin
• din
• djinn
• fin
• finn
• gin
• grin
• kin
• linn
• linne

Kids Definition

in

1 of 6 preposition

(ˈ)in 

ən,

ᵊn

1

a

—used to show enclosing, including, or placing within limits

in the lake

wounded in the leg

in the summer

in a minute

b

: into sense 1a

went in the house

don't come in here with those muddy feet

2

—used to show means or medium

written in pencil

works in plastics

photographs in color

3

a

—used to show a state or condition

we're in trouble

is made in three sizes

in power

in love

b

: into sense 2a

broke in pieces

4

—used to show manner or purpose

said in reply

5

—used to show the larger member of a ratio

one in five

in

2 of 6 adverb

ˈin 

1

a

: to or toward the inside

went in and closed the door

b

: to or toward a place

flew in yesterday

c

: so as to be or seem near

play close in

d

: into the midst of something

mix in the flour

e

: to or at its proper place

fit a piece in

f

: so as to be in agreement

fell in with our plans

2

a

: on the inner side : within

everyone is in

b

: on good terms

in with the right people

c

: in fashion

boots are in this year

d

: at hand : on hand

the evidence was in

harvests are in

in

3 of 6 adjective

ˈin 

1

a

: being inside or within

the in part

b

: being in power

the in party

2

: directed or bound inward : incoming

the in train

3

a

: very fashionable

the in thing to do

the in place to go

b

: very aware of and taking part in what is new and fashionable

the in crowd

in-

4 of 6 prefix

variants or il- or im- or ir-

: not : non-, un-

—usually il- before l

illogical

, im- before b, m, or p

imbalance

immoral

impractical

, ir- before r

irreducible

, and in- before other sounds

inconclusive

in-

5 of 6 prefix

variants or il- or im- or ir-

1

: in : within : into : toward : on

—usually il- before l, im- before b, m, or p, ir- before r, and in- before other sounds

infiltrate

2

: en- sense 2

imperil

-in

6 of 6 noun suffix

ən

: chemical compound

stearin

insulin

niacin

Etymology

Prefix

derived from Latin in- "not"

Prefix

derived from Latin in "in, into"

Noun suffix

derived from Latin -ina, -inus (adjective suffixes)

Medical Definition

in

1 of 2 abbreviation

inch

In

2 of 2 symbol

indium

Legal Definition

in

preposition

: under the law of : based on

brought an action in negligence

—National Law Journal