on

Adjective

on (not comparable)

1. In the state of being active, functioning or operating.

   Antonym: off

   All the lights are on, so they must be home.

2. Happening; taking place; being or due to be put into action.

   We had to ration our food because there was a war on.

   Some of the cast went down with flu, but the show's still on.

   That TV programme that you wanted to watch is on now.

   This is her last song. You're on next!

   Are we still on for tonight?

   Mike just threw coffee onto Paul's lap. It's on now.

   England need a hundred runs, with twenty-five overs remaining. Game on!

   1. (informal) Of a person, used to express agreement to or acceptance of a proposal or challenge made by that person; most commonly with subject "you" (see you're on).

      "Five bucks says the Cavs win tonight." ―"You're on!"

      If he wants a fight, he's on!

3. Fitted; covering or being worn.

   Your feet will soon warm up once your socks are on.

   I was trying to drink out of the bottle while the top was still on!

4. (postpositive) Of a stated part of something, oriented towards the viewer or other specified direction.

   The photograph shows the UFO side on.

   edge on, side on, end on, face on

5. (chiefly UK, informal, usually negative) Acceptable, appropriate.

   It's not fair to do that – it's just not on.

   • 1998 May 22, Phoenix Gamma, “If I was owned Nintendo...”, in alt.games.video.nintendo-64 (Usenet):

     This kind of over-packaging of goods is completely not on.

   • 2003 August 12, DAB sounds worse than FM, “Gerg Dyke's Speech at Radio Festival”, in alt.radio.digital (Usenet):

     so Simon Nelson saying on Feedback "we'd prefer it if everybody listened to digital radio via DAB" is completely not on at all.

6. (often negative) Possible; capable of being successfully carried out.

   Climbing up that steep ridge isn't on. We'll have to find another route.

   He'd like to play the red next to the black spot, but that shot isn't on.

7. (e.g. of points in a game) Available; remaining.

   Smith is 25 points ahead with only 23 on.

8. (baseball, informal) Having reached a base as a runner and being positioned there, awaiting further action from a subsequent batter.
   • 2019 February 24, Chris Kennedy, “Aggies Earn Series Win Over Yale in Sunday Finale”, in New Mexico State University Athletics‎:

     With one out and no men on, Tristen Carranza belted a ball to the opposite field for a solo home run to put the NM State deficit at just 2-1.

   • 2019 April 6, Daniel Martinez-Krams, “Baseball Falls Short in Game 2 of UCLA Series”, in The Stanford Daily‎:

     Although Stanford was outhit 15-6, the Cardinal stranded eight runners to UCLA's three, hitting just 3-15 with runners on compared to the Bruin's 9-22.

9. (cricket) Within the half of the field on the same side as the batsman's legs; the left side for a right-handed batsman.

   Synonym: leg Antonym: off

   The captain moved two fielders to the on side.

   Ponsonby-Smythe hit a thumping on drive.

10. (snooker, postpositive) Of a ball, being the next in sequence to be potted, according to the rules of the game.

    If the player fails to hit the ball on, it's a foul.

11. (acting, drama, roleplaying games) Acting in character.
12. (informal, of a person) Performative or funny in a wearying manner.

    He always has to be on, it's so exhausting.

13. (euphemistic) Menstruating.
    • 2011, Hollie Smith Netmums, You and Your Tween: Managing the years from 9 to 13, Hachette, →ISBN:

      It still gets in the way of her doing things like swimming, and she avoids sleepovers when she's "on".

Adverb

on (not comparable)

For idiomatic meanings of phrasal verbs, such as carry on, hang on, have on, try on, etc., please see the individual entries.

1. To an operating state.

   turn the television on

2. So as to cover or be fitted.

   The lid wasn't screwed on properly.

   Put on your hat and gloves.

3. Along, forwards (continuing an action), onwards.

   The policeman moved the tramp on.

   Drive on past the railway station.

   From now on things are going to be different.

   rock on

   • 2012 May 5, Phil McNulty, “Chelsea 2-1 Liverpool”, in BBC Sport‎:

     He met Luis Suarez's cross at the far post, only for Chelsea keeper Petr Cech to show brilliant reflexes to deflect his header on to the bar. Carroll turned away to lead Liverpool's insistent protests that the ball had crossed the line but referee Phil Dowd and assistant referee Andrew Garratt waved play on, with even a succession of replays proving inconclusive.

4. In continuation, at length.

   and so on

   He rambled on and on.

5. (obsolete in the US) Later.

   Ten years on, nothing had changed in the village.

6. Of betting odds, denoting a better-than-even chance. See also odds-on.

   Antonym: against

   That horse is twenty-to-one on, so you need to stake twenty pounds just to win one pound.

7. (snooker) Of a ball, into a pottable position.

   The black was previously unavailable, but in potting that red, he's now pushed the black on.

Preposition

on

1. Indicating position or location.
   1. Positioned at the upper surface of, touching from above.

      A vase of flowers stood on the table.

      Please lie down on the couch.

      The parrot was sitting on Jim's shoulder.

      • 1845, Henry Wadsworth Longfellow, The Bridge:

        I stood on the bridge at midnight.

   2. Positioned at or resting against the outer surface of; attached to.

      He had a scar on the side of his face.

      There is a dirty smudge on this window.

      The painting hangs on the wall.

      The fruit ripened on the trees.

      Should there be an accent on the "e"?

   3. Covering.

      He wore old shoes on his feet.

   4. At or in (a geographical location or position).

      The lighthouse that you can see is on the mainland.

      The suspect is thought to still be on the campus.

   5. At (a relative spatial position).

      We live on the edge of the city.

      on the left, on the right, on the side, on the bottom

   6. Near; adjacent to; alongside; just off.

      The fleet is on the American coast.

      Croton-on-Hudson, Rostov-on-Don, Southend-on-Sea

   7. Aboard (a mode of transport, especially public transport, or transport that one sits astride or uses while standing).

      on a bus, on a train, on a plane, on a ferry, on a yacht

      on a bicycle, on a motorbike, on a horse, on a scooter

2. Expressing figurative placement, burden, or attachment.

   All of the responsibility is on him.

   I put a bet on the winning horse.

3. Denoting physical contact or interaction with an object, such as impact or application of force.
   1. With verbs describing an action of pushing, pulling, pressing, etc., designates the thing to which force is applied.

      tug on the rope; push hard on the door

   2. With verbs describing an action of hitting, rubbing, scratching, binding against, etc., designates the thing impacted or contacted.

      I stubbed my toe on an old tree stump.

      I caught my fingernail on the door handle.

      The rope snagged on a branch.

   3. Denoting performance or action by contact with the surface, upper part, or outside of anything; hence, by means of; with.

      to play on a violin or piano

4. Supported by (the specified part of itself).

   A table can't stand on two legs.

   After resting on his elbows, he stood on his toes, then walked on his heels.

5. (UK) At (a certain value or level).

   The Tories are on twenty-five percent in this constituency.

   The blue team are on six points and the red team on five.

6. At (a certain position within a sequence).

   I'm on question four.

7. At or during the date or day of.

   Born on the 4th of July.

   On Sunday I'm busy. I'll see you on Monday.

   Can I see you on a different day?

8. (UK, especially in sports reporting) At (a given time after the start of something).

   Smith scored again on twelve minutes, doubling Mudchester Rovers' lead.

   • 2011 September 24, Aled Williams, “Chelsea 4-1 Swansea”, in BBC Sport:

     The Spain striker had given Chelsea the lead on 29 minutes but was shown a straight red card 10 minutes later for a rash challenge on Mark Gower.

9. At (an instant or cusp).

   on the stroke of midnight; on the "B" of "Bang!"

   on the point of leaving; on the verge of giving up

10. Dealing with the subject of; about; concerning.

    I was reading a book on history.

    The city hosted the World Summit on the Information Society

    I have no opinion on this subject.

    • 1869 May, Anthony Trollope, “Lady Milborough as Ambassador”, in He Knew He Was Right, volume I, London: Strahan and Company, […], →OCLC, page 85:

      [...] I received a note from that gentleman on a most trivial matter. I answered it as trivially.

11. Indicating a means or medium.

    I saw it on television.

    Can't you see I'm on the phone?

    My favorite shows are on BBC America.

    The Beatles' appearance on the Ed Sullivan Show is on YouTube.

    The film was released on DVD.

12. Indicating the target of, or thing affected by, an event or action.

    They planned an attack on London.

    The soldiers mutinied and turned their guns on their officers.

    Her words made a lasting impression on my mind.

    What will be the effect on morale?

13. (informal) In the possession of.

    I haven't got any money on me.

14. Because of; due to; upon the basis of (something not yet confirmed as true).

    to arrest someone on suspicion of bribery

    to contact someone on a hunch

15. (also often 'upon') At the time of (and often because of).

    On Jack's entry, William got up to leave.

    On the addition of ammonia, a chemical reaction begins.

16. (also often 'upon') Arrived or coming into the presence of.

    I need to get my planting done, as the season will soon be on us.

    Before we knew it, the forest was on us, and the air grew colder and damper.

17. Paid for by.

    The drinks are on me tonight, boys.

    The meal is on the house.

    I paid for the airfare and meals for my family, but the hotel room was on the company.

18. Toward; for; indicating the object of an emotion.

    Have pity or compassion on him.

20. (especially Ireland) Indicating the person experiencing an emotion, cold, thirst, hunger, etc.

    I had a terrible thirst on me.

    • 2013 February 27, Rosemary Sutcliff, The Shining Company, Random House, →ISBN:

      ' […] the hunger is on me to carry my sword in distant places.' Mynyddog bowed his head.

    • 2017 January 24, Ruth Gilligan, Nine Folds Make a Paper Swan, Tin House Books, →ISBN:

      “Christ, the thirst on me.” “Sure, it's serious work, all that talk of independence.” The theater's stained-glass doors had first flung open in 1904, all in the hope of “rewriting the Irish identity,” of using culture in the fight […]

    • 2017 August 29, Ralph Peters, Judgment at Appomattox: A Novel, Forge Books, →ISBN, page 18:

      “I've got the hunger on me, I do.” Riordan snorted. Hardly a man knew hunger as he did. The prison rations at Point Lookout, spare enough, had been a feast compared to the black years in Ireland. […]

21. Indicating a means of subsistence or sustenance.

    They lived on ten dollars a week.

    The dog survived three weeks on rainwater.

    • 1950s, UK Egg Marketing Board advertising slogan.

      Go to work on an egg.

22. Engaged in or occupied with (an action or activity).

    He's on his lunch break.

    I'm on nights all this week.

    on vacation; on holiday; on a mission; on the job; on the fiddle

24. Regularly taking (a drug).

    You've been on these antidepressants far too long.

26. Under the influence of (a drug, or something that is causing drug-like effects).

    He's acting crazy because he's on crack right now.

27. In addition to; besides; indicating multiplication or succession in a series.

    heaps on heaps of food

    mischief on mischief; loss on loss

28. Indicating dependence or reliance.

    I depended on them for assistance.

    He will promise on certain conditions.

29. Serving as a member of.

    He is on the jury; I am on the committee.

30. By virtue of; with the pledge of.

    He affirmed or promised on his word, or on his honour.

    1. (informal, chiefly in set phrases) Ellipsis of I swear on: on my life, on God, on everything, etc.
31. To the account or detriment of; denoting imprecation or invocation, or coming to, falling, or resting upon.

    On us be all the blame.

    A curse on him!

    Please don't tell on her and get her in trouble.

    He turned on her and has been her enemy ever since.

    He went all honest on me, making me listen to his confession.

    • 1611, The Holy Bible, […] (King James Version), London: […] Robert Barker, […], →OCLC, Matthew 27:25:

      His blood be on vs, and on our children.

32. (especially when numbers of combatants or competitors are specified) Against; in opposition to.

    The fight was three on one, and he never stood a chance.

33. (philosophy, logic) According to, from the standpoint of; expressing what must follow, whether accepted or not, if a given premise or system is assumed true.
    • 2021, Gavin Ortlund, Why God Makes Sense in a World That Doesn't: The Beauty of Christian Theism, Grand Rapids, MI: Baker Academic, →ISBN:

      On naturalism, it is therefore difficult to find a ground for ultimate moral hope.

34. (snooker) In a position of being able to pot (a given ball).

    All the way around the table, off four cushions, and ... and he's on the black!

35. (mathematics) Having as identical domain and codomain.

    a function on ${\displaystyle \mathbb {R} }$

36. (mathematics) Having ${\displaystyle V^{n}}$ as domain and V as codomain, for the specified set V and some integer n.

    an operator on ${\displaystyle \mathbb {Z} }$

37. (mathematics) Generated by.

    the free group on four letters

38. (mathematics, uncommon) Divided by.

    Synonym: over

    Twenty on three.

39. (obsolete or dialect, regional) Of.

    I never seen 'im, and that's the truth on it.

    • 1599 (first performance), William Shakespeare, “The Tragedie of Iulius Cæsar”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act I, scene ii]:

      Be not jealous on me.

    • c. 1606 (date written), William Shakespeare, “The Tragedie of Macbeth”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act I, scene iii]:

      Or have we eaten on the insane root / That takes the reason prisoner?

40. (obsolete) At the peril of, or for the safety of.
    • a. 1701 (date written), John Dryden, “The First Book of Homer’s Ilias”, in The Miscellaneous Works of John Dryden, […], volume IV, London: […] J[acob] and R[ichard] Tonson, […], published 1760, →OCLC, page 415:

      Hence on thy life: the captive maid is mine; / Whom not for price or pray'rs I will reſign: [...]

Verb

on (third-person singular simple present ons, present participle oning or onning, simple past and past participle oned or onned)

1. (Singapore, Philippines, Malaysia, Nigeria, transitive, colloquial) To switch on.

   Synonym: turn on

   Can you on the light?

Alternative forms

• ohn

Preposition

on

1. (UK dialectal, Scotland) Without. (Can we add an example for this sense?)

Noun

on

1. In the Japanese language, a pronunciation, or reading, of a kanji character that was originally based on the character's pronunciation in Chinese, contrasted with kun.

   Most kanji have two kinds of reading, called "on" and "kun".