WordReference Random House Learner's Dictionary of American English © 2015
on /ɑn, ɔn/USA pronunciation prep.  so as to be or to remain supported by:Put the package on the table. so as to be attached to or unified with:There is a label on the jar. so as to be a covering or wrapping for:Put the blanket on the baby. in connection, association, or cooperation with:to serve on a jury. so as to be a supporting part or base of:legs on a chair. (used to show that the preceding noun has the following noun as its place, location, situation, etc.):an ugly scar on the face. very close to; at the edge of:a house on the lake. in the direction of:to sail on a southerly course. using as a means of carrying or of supporting or providing movement:arrived on the noon plane. by the agency or means of:drunk on wine. directed against or toward:She played a joke on him. having as a subject; being about (something):a new book on dogs. in a state, condition, or process of:The workers are on strike. engaged in or involved with:I'm on the second chapter of the book. subject to:If there is a doctor on call it means that a doctor can be summoned quickly in an emergency. having as a source or agent:He came to depend on his friends. having as a basis or ground:on my word of honor. assigned to or working at:Who's on duty today? (used with days and dates) at the time mentioned:The train arrives every hour on the hour (= at one, two, three o'clock, etc.) at the time or occasion of:You have to pay cash on delivery (= at the time delivery is made). within the required limits of:The train arrived on time. having as the object or end of motion:The demonstrators marched on the capital. having as the object or the goal of action, thought, desire, etc.:to gaze on a scene. having as the subject or reference; with respect to:What are your views on rock music? Informal Termspaid for by, esp. as a treat or gift:Dinner is on me. taking or using as a measure or cure to improve one's health, energy, etc.:He's on a low-salt diet. regularly taking or addicted to:She's not on drugs anymore. Informal Termswith; carried by:I have no money on me. so as to disturb or affect in a bad way:My hair dryer broke on me. having as a risk or unfortunate result:on pain of death. in addition to:millions on millions of stars.
adv.  in, into, or onto a position of being supported or attached:Sew the buttons on. in, into, or onto a position of covering or wrapping:Put your raincoat on. tightly attached to a thing, such as for support:Hold on! toward a place, point, activity, or object:to look on while others work. forward, onward, or along, such as in any course or process later on:further on. with continuous activity:continued on with his job. into or in active operation or performance:Turn the gas on.
adj. [be +  ~] operating or in use:Is the radio on? taking place; occurring:Don't you know there's a war on? being broadcast:What's on tonight, anything interesting to watch? scheduled or planned:Do you have anything on for tomorrow?
  • 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.
    Idiomson and off, with periods of time in between; intermittently. Idiomson and on, at great length:to chatter on and on.Compareat, in. See about.

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
  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
  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' also found in these entries:

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

Look up "on" at Merriam-Webster
Look up "on" at dictionary.com

In other languages: Spanish | French | Italian | Portuguese | German | Russian | Polish | Romanian | Czech | Greek | Turkish | Chinese | Japanese | Korean | Arabic

Download free Android and iPhone apps

Android AppiPhone App
Report an inappropriate ad.