on

1 of 7

preposition

ˈȯn  ˈän 

1

a

—used as a function word to indicate position in contact with and supported by the top surface of

the book is lying on the table

b

—used as a function word to indicate position in or in contact with an outer surface

the fly landed on the ceiling

I have a cut on my finger

paint on the wall

c

—used as a function word to indicate position in close proximity with

a village on the sea

stay on your opponent

d

—used as a function word to indicate the location of something

on the left

on the south side of the house

on the farm

2

a

—used as a function word to indicate a source of attachment or support

on a string

stand on one foot

hang it on a nail

b

—used as a function word to indicate a source of dependence

you can rely on me

feeds on insects

lives on a pension

c

—used as a function word to indicate means of conveyance

on the bus

d

—used as a function word to indicate presence in the possession of

had a knife on him

3

—used as a function word to indicate a time frame during which something takes place

a parade on Sunday

or an instant, action, or occurrence when something begins or is done

on cue

on arriving home, I found your letter

news on the hour

cash on delivery

4

archaic : of

5

a

—used as a function word to indicate manner of doing something

—often used with the

on the sly

keep everything on the up-and-up

b

—used as a function word to indicate means or agency

cut myself on a knife

talk on the telephone

c

—used as a function word to indicate a medium of expression

on stage

best show on television

6

a(1)

—used as a function word to indicate active involvement in a condition or status

on the increase

on the lookout

(2)

: regularly using or showing the effects of using

on drugs

b

—used as a function word to indicate involvement or participation

on tour

on the team

on duty

c

—used as a function word to indicate inclusion

put it on the agenda

d

—used as a function word to indicate position or status in proper relationship with a standard or objective

on schedule

7

a

—used as a function word to indicate reason, ground, or basis (as for an action, opinion, or computation)

I have it on good authority

on one condition

the interest will be 10 cents on the dollar

b

—used as a function word to indicate the cause or source

profited on the sale of stock

c

—used as a function word to indicate the focus of obligation or responsibility

drinks are on the house

put the blame on me

8

a

—used as a function word to indicate the object of collision, opposition, or hostile action

bumped my head on a limb

an attack on religion

pulled a gun on me

b

—used as a function word to indicate the object with respect to some disadvantage, handicap, or detriment

has three inches in height on me

a 3-game lead on the second-place team

the joke's on me

9

a

—used as a function word to indicate destination or the focus of some action, movement, or directed effort

crept up on him

feast your eyes on this

working on my skiing

made a payment on the loan

b

—used as a function word to indicate the focus of feelings, determination, or will

have pity on me

keen on sports

a curse on you

c

—used as a function word to indicate the object with respect to some misfortune or disadvantageous event

the crops died on them

d

—used as a function word to indicate the subject of study, discussion, or consideration

a book on insects

reflect on that a moment

agree on price

e

: with respect to

go light on the salt

short on cash

10

—used as a function word to indicate reduplication or succession in a series

loss on loss

trouble on trouble

on

2 of 7

adverb

1

a

: in or into a position of contact with an upper surface especially so as to be positioned for use or operation

put the plates on

b

: in or into a position of being attached to or covering a surface

especially : in or into the condition of being worn

put his new shoes on

2

a

: forward or at a more advanced point in space or time

went on home

later on

b

: in continuance or succession

rambled on

and so on

3

: into operation or a position permitting operation

switched the light on

on

3 of 7

adjective

1

: engaged in an activity or function (such as a dramatic role)

2

a(1)

: being in operation

The radio is on.

(2)

: placed so as to permit operation

The switch is on.

b

: taking place or being broadcast

The game is on.

3

: aware of something

—usually used with to

My boss was on to me.

4

: intended, planned

has nothing on for tonight

5

British : talking or harping incessantly

—used with about

6

chiefly British : regarded as possible or feasible

—usually used in negative constructions

7

a

: engaged in or as if in a performance

The comedian was always on.

b

: being at a high level of performance

ON

4 of 7

abbreviation

variants or Ont

Ontario

-on

5 of 7

noun suffix (1)

: chemical compound not a ketone or other oxo compound

parathion

-on

6 of 7

noun suffix (2)

1

: subatomic particle

nucleon

2

a

: unit : quantum

photon

magneton

b

: basic hereditary component

cistron

operon

-on

7 of 7

noun suffix (3)

: noble gas

radon

Synonyms

Preposition

• about
• apropos
• apropos of
• as far as
• as for
• as regards
• as respects
• as to
• concerning
• of
• regarding
• respecting
• touching
• toward
• towards

Adverb

• ahead
• forth
• forward
• onward
• onwards

Adjective

• active
• alive
• functional
• functioning
• going
• live
• living
• operating
• operational
• operative
• running
• working

Examples of on in a Sentence

Preposition

There is a lot of frosting on the cake.

books on sports heroes are my favorite reading matter

Adverb

We're far on with our project.

I'll come by to help you later on.

Adjective

The lid is on tight.

The band will be on in 10 minutes.

He is on tomorrow from 6 a.m. to 6 p.m.

Recent Examples on the Web

Preposition

Southwest reports third-quarter results before the market opens on Thursday. —Rohan Goswami, CNBC, 24 Oct. 2024

When an emaciated dwarf sperm whale calf washed ashore on a Florida beach last month, officials brought the distressed mammal to veterinarians for further examination. —Leah Sarnoff, ABC News, 24 Oct. 2024

This Time Each Year premieres Thursday, Oct. 24, at 8 p.m. ET on Hallmark Mystery. —Dana Rose Falcone, People.com, 24 Oct. 2024

The comforters on our list range from just over $100 to $300-plus, depending on the size. —Suzy Forman, SELF, 24 Oct. 2024

Word History

Etymology

Preposition, Adverb, and Adjective

Middle English an, on, preposition & adverb, from Old English; akin to Old High German ana on, Greek ana up, on

Noun suffix (1)

International Scientific Vocabulary, alteration of -one

Noun suffix (2)

from -on (in ion)

Noun suffix (3)

New Latin, from -on (in argon)

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

Adjective

circa 1541, in the meaning defined at sense 1

Kids Definition

on

1 of 3 preposition

(ˈ)ȯn 

(ˈ)än

1

a

: in contact with and supported by

the book on the table

b

: in a position in contact with or near

a fly on the wall

a town on the river

c

—used to indicate the location of something

on the other side of the house

on the right

2

a

—used to indicate means of being attached or supported

on a string

stood on one foot

hang your coat on the peg

you can rely on me

lives on insects

b

—used to indicate means of being carried

rode on a horse

went on the bus

have only five dollars on me

3

—used to indicate a time or an instance when something takes place

on arriving home, I found your letter

arrived on Monday

news on the hour

4

a

—used to indicate the way something is done

told her on the sly

b

—used to indicate what something is done with or done by

cut on broken glass

talk on the phone

type on a keyboard

displayed on a TV screen

5

a

: involved with or participating in : busy with

on a committee

on tour

b

: in a state or process of

on fire

on the increase

c

: in keeping with a goal or objective

on schedule

6

a

—used to indicate a reason or basis

on one condition

interest of 10 cents on the dollar

b

—used to indicate who or what is responsible

this treat is on me

blamed it on the weather

7

—used to indicate someone or something an action or feeling is directed toward

was creeping up on us

have pity on me

the joke's on you

8

a

: concerning, about

a book on cats

agree on price

b

: with respect to

go light on the salt

short on cash

9

: following in series

loss on loss

on

2 of 3 adverb

ˈȯn,

ˈän

1

: in or into contact with a surface

put the kettle on

has new shoes on

2

: forward in space, time, or action

went on home

on came the storm

getting on in years

3

: from one to another

pass the word on

and so on

4

: into operation or a position allowing operation

turn the light on

on

3 of 3 adjective

ˈȯn,

ˈän

1

: doing an activity (as a role in a play)

you're on next

2

a

: being in operation

the radio is on

b

: set so as to permit operation

the switch is on

c

: taking place or being broadcast

the game is on

3

: having been planned

has nothing on for tonight

Medical Definition

on

preposition

ˈȯn, ˈän 

: regularly using or showing the effects of using

is on an ACE inhibitor to control hypertension

was on drugs for two years before entering rehab