WordReference Random House Learner's Dictionary of American English © 2017
on /ɑn, ɔn/USA pronunciation   prep. 
  1. so as to be or to remain supported by:Put the package on the table.
  2. so as to be attached to or unified with:There is a label on the jar.
  3. so as to be a covering or wrapping for:Put the blanket on the baby.
  4. in connection, association, or cooperation with:to serve on a jury.
  5. so as to be a supporting part or base of:legs on a chair.
  6. (used to show that the preceding noun has the following noun as its place, location, situation, etc.):an ugly scar on the face.
  7. very close to;
    at the edge of:a house on the lake.
  8. in the direction of:to sail on a southerly course.
  9. using as a means of carrying or of supporting or providing movement:arrived on the noon plane.
  10. by the agency or means of:drunk on wine.
  11. directed against or toward:She played a joke on him.
  12. having as a subject;
    being about (something):a new book on dogs.
  13. in a state, condition, or process of:The workers are on strike.
  14. engaged in or involved with:I'm on the second chapter of the book.
  15. subject to:If there is a doctor on call it means that a doctor can be summoned quickly in an emergency.
  16. having as a source or agent:He came to depend on his friends.
  17. having as a basis or ground:on my word of honor.
  18. assigned to or working at:Who's on duty today?
  19. (used with days and dates) at the time mentioned:The train arrives every hour on the hour (= at one, two, three o'clock, etc.)
  20. at the time or occasion of:You have to pay cash on delivery (= at the time delivery is made).
  21. within the required limits of:The train arrived on time.
  22. having as the object or end of motion:The demonstrators marched on the capital.
  23. having as the object or the goal of action, thought, desire, etc.:to gaze on a scene.
  24. having as the subject or reference;
    with respect to:What are your views on rock music?
  25. Informal Termspaid for by, esp. as a treat or gift:Dinner is on me.
  26. taking or using as a measure or cure to improve one's health, energy, etc.:He's on a low-salt diet.
  27. regularly taking or addicted to:She's not on drugs anymore.
  28. Informal Termswith;
    carried by:I have no money on me.
  29. so as to disturb or affect in a bad way:My hair dryer broke on me.
  30. having as a risk or unfortunate result:on pain of death.
  31. in addition to:millions on millions of stars.

adv. 
  1. in, into, or onto a position of being supported or attached:Sew the buttons on.
  2. in, into, or onto a position of covering or wrapping:Put your raincoat on.
  3. tightly attached to a thing, such as for support:Hold on!
  4. toward a place, point, activity, or object:to look on while others work.
  5. forward, onward, or along, such as in any course or process later on:further on.
  6. with continuous activity:continued on with his job.
  7. into or in active operation or performance:Turn the gas on.

adj. [be +  ~]
  1. operating or in use:Is the radio on?
  2. taking place;
    occurring:Don't you know there's a war on?
  3. being broadcast:What's on tonight, anything interesting to watch?
  4. scheduled or planned:Do you have anything on for tomorrow?
  5. Informal Terms
    • behaving in a very animated or theatrical manner:He never stops and just relaxes; he's always on.
    • functioning or performing at one's best:The pitcher is really on today.
Idioms
  1. Idiomson and off, with periods of time in between;
    intermittently.
  2. Idiomson and on, at great length:to chatter on and on.Compareat, in.
    See about.


WordReference Random House Unabridged Dictionary of American English © 2017
on  (on, ôn),USA pronunciation prep. 
  1. so as to be or remain supported by or suspended from:Put your package down on the table; Hang your coat on the hook.
  2. so as to be attached to or unified with:Hang the picture on the wall. Paste the label on the package.
  3. so as to be a covering or wrapping for:Put the blanket on the baby. Put aluminum foil on the lamb chops before freezing them.
  4. in connection, association, or cooperation with;
    as a part or element of:to serve on a jury.
  5. so as to be a supporting part, base, backing, etc., of:a painting on canvas;mounted on cardboard;legs on a chair.
  6. (used to indicate place, location, situation, etc.):a scar on the face;the book on the table;a house on 19th Street.
  7. (used to indicate immediate proximity):a house on the lake; to border on absurdity.
  8. in the direction of:on the left; to sail on a southerly course.
  9. (used to indicate a means of conveyance or a means of supporting or supplying movement):on the wing; This car runs on electricity. Can you walk on your hands? I'll be there on the noon plane.
  10. by the agency or means of:drunk on wine;talking on the phone;I saw it on television.
  11. in addition to:millions on millions of stars.
  12. with respect or regard to (used to indicate the object of an action directed against or toward):Let's play a joke on him. Write a critical essay on Shakespeare.
  13. in a state or condition of;
    in the process of:on strike; The house is on fire!
  14. subject to:a doctor on call.
  15. engaged in or involved with:He's on the second chapter now.
  16. (used to indicate a source or a person or thing that serves as a source or agent):a duty on imported goods; She depends on her friends for encouragement.
  17. (used to indicate a basis or ground):on my word of honor; The movie is based on the book.
  18. (used to indicate risk or liability):on pain of death.
  19. (used to indicate progress toward or completion of an objective):We completed the project on budget.
  20. assigned to or occupied with;
    operating:Who's on the switchboard this afternoon?
  21. [Informal.]so as to disturb or affect adversely:My hair dryer broke on me.
  22. Informal Termspaid for by, esp. as a treat or gift:Dinner is on me.
  23. taking or using as a prescribed measure, cure, or the like:The doctor had her on a low-salt diet.
  24. regularly taking or addicted to:He was on drugs for two years.
  25. Informal Termswith;
    carried by:I have no money on me.
  26. (used to indicate time or occasion):on Sunday; We demand cash on delivery.
  27. (used to indicate the object or end of motion):to march on the capital.
  28. (used to indicate the object or end of action, thought, desire, etc.):to gaze on a scene.
  29. (used to indicate subject, reference, or respect):views on public matters.
  30. (used to indicate an encounter):The pickpocket crept up on a victim.
  31. on the bow, [Naut.]bow3 (def. 7).

adv. 
  1. in, into, or onto a position of being supported or attached:Sew the buttons on.
  2. in, into, or onto a position of covering or wrapping:Put your raincoat on.
  3. fast to a thing, as for support:Hold on!
  4. toward a place, point, activity, or object:to look on while others work.
  5. forward, onward, or along, as in any course or process:further on.
  6. with continuous activity:to work on.
  7. into or in active operation or performance:Turn the gas on.
  8. Idiomson and off, off (def. 22a).
  9. Idiomson and on, at great length, so as to become tiresome:They rambled on and on about their grandchildren.

adj. 
  1. operating or in use:The television set was on. Is your brake on?
  2. taking place;
    occurring:Don't you know there's a war on?
  3. performing or broadcasting:The radio announcer told us we were on.
  4. Informal Terms
    • behaving in a theatrical, lively, or ingratiating way:Around close friends, one doesn't have to be on every minute.
    • functioning or performing at one's best:When she's on, no other tennis player is half as good.
  5. scheduled or planned:Anything on after supper?
  6. Sport[Baseball.]positioned on a base or bases:They had two men on when he hit the home run.
  7. Sport[Cricket.]noting that side of the wicket, or of the field, on which the batsman stands.
  8. Idiomson to,  aware of the true nature, motive, or meaning of:I'm on to your little game.

n. 
  1. Sport[Cricket.]the on side.
  • bef. 900; Middle English on, an, Old English: on, in, to; cognate with Dutch aan, German an, Old Norse ā, Gothic ana; akin to Greek aná up, upon (see ana-)

On  (on),USA pronunciation n. 
  1. Bible, Place NamesBiblical name of  Heliopolis. 

ON, 
  • Language VarietiesOld Norse.
  • Also,  ON., O.N. 
  • AbbreviationsOntario, Canada (approved for postal use).

  • -on1 , 
  • Physicsa suffix used in the names of subatomic particles (gluon;
    meson;
    neutron
    ), quanta (graviton), and other minimal entities or components (cistron;
    codon;
    magneton;
    photon
    ).
    • compare proton probably extracted from ion

    -on2 , 
  • Chemistrya suffix used in the naming of inert gaseous elements:neon.
    • Greek -on, neuter of -os adjective, adjectival ending

    WordReference Random House Unabridged Dictionary of American English © 2017
    ON, +
  • AbbreviationsOntario, Canada (approved for postal use).


  • Collins Concise English Dictionary © HarperCollins Publishers::

    on /ɒn/ prep
    1. in contact or connection with the surface of; at the upper surface of: an apple on the ground, a mark on the table cloth
    2. attached to: a puppet on a string
    3. carried with: I've no money on me
    4. in the immediate vicinity of; close to or along the side of: a house on the sea, this verges on the ridiculous!
    5. within the time limits of a day or date: he arrived on Thursday
    6. being performed upon or relayed through the medium of: what's on the television?
    7. at the occasion of: on his retirement
    8. used to indicate support, subsistence, contingency, etc: he lives on bread, it depends on what you want
    9. regularly taking (a drug): she's on the pill
    10. addicted to: he's on heroin
    11. by means of (something considered as a mode of transport) (esp in such phrases as on foot, on wheels, on horseback, etc)
    12. in the process or course of: on a journey, on strike
    13. concerned with or relating to: a tax on potatoes, a programme on archaeology
    14. used to indicate the basis, grounds, or cause, as of a statement or action: I have it on good authority
    15. against: used to indicate opposition: they marched on the city at dawn
    16. used to indicate a meeting or encounter: he crept up on her
    17. (used with an adjective preceded by the) indicating the manner or way in which an action is carried out: on the sly, on the cheap
    18. informal staked or wagered as a bet: ten pounds on that horse
    19. charged to: the drinks are on me
    adv (often used as a particle)
    1. in the position or state required for the commencement or sustained continuation, as of a mechanical operation: the radio's been on all night
    2. attached to, surrounding, or placed in contact with something
    3. in a manner indicating continuity, persistence, concentration, etc: don't keep on about it, the play went on all afternoon
    4. in a direction towards something, esp forwards; so as to make progress: we drove on towards London, march on!
    5. on and off, off and onintermittently; from time to time
    6. on and onwithout ceasing; continually
    adj
    1. functioning; operating: turn the switch to the on position
    2. (postpositive) informal performing, as on stage: I'm on in five minutes
    3. definitely taking place: the match is on for Friday, their marriage is still on
    4. tolerable, practicable, acceptable, etc: your plan just isn't on
    5. on atinformal nagging: she was always on at her husband
    6. (of a bowler) bowling
    n
    1. (modifier) relating to or denoting the leg side of a cricket field or pitch: the on side, an on drive
    2. (in combination) used to designate certain fielding positions on the leg side: long-on, mid-on
    Etymology: Old English an, on; related to Old Saxon an, Old High German, Gothic ana



    ON abbreviation for
    1. Old Norse
    2. (esp in postal addresses) Ontario



    On /ɒn/ n
    1. the ancient Egyptian and biblical name for Heliopolis



    -on suffix forming nouns
    1. indicating a chemical substance: interferon, parathion
    2. (in physics) indicating an elementary particle or quantum: electron, photon
    3. (in chemistry) indicating an inert gas: neon, radon
    4. (in biochemistry) a molecular unit: codon, operon
    Etymology: from ion



    'on' also found in these entries:

    Forum discussions with the word(s) "on" in the title:


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