Longman Dictionary of Contemporary English - on

~1 prep 1 touching or being supported by a particular surface  (The plate's on the table. | You have mud on your shoes. | The answer is written on page 25.) 2 hanging from, supported by or connected to a particular thing  (Stand on one foot. | pictures stuck on the wall | a ball on a string) 3 a) in a particular place, building or area of land  (Several bombs landed on the runway. | He grew up on a ranch in California.) b) AmE in a particular road  (We live on Mulberry Drive. | I met Amy on the street the other day.) 4 in a particular direction  (On my right sat the Chancellor. | As the troops marched on the city, the leaders planned their escape.) 5 used to show the person or thing affected by an action or someone's behaviour  (a tax on cigarettes | The divorce has had a particularly bad effect on the children.) 6 on one of the sides of something such as a river or road  (a cafe on the river | a beautiful village on the Austrian border | trees on both sides of the street) 7 on Friday/August 2nd/my birthday at some time during a particular day  (They arrive on Tuesday. | I was born on July 1st.) 8 about a particular subject  (a book on India | advice on what to wear) 9 in a bus, train, aircraft etc  (Everyone on the plane was frightened. | He managed to be on the first train back to London.)  (- see also on foot foot1 (2), on horseback horseback) 10 used to say what food someone needs to survive, what fuel1 (1) something needs to operate etc  (We can't live on rice and water forever. | Many cars nowadays run on lead free petrol.) 11 used to say what money people use to live, the amounts of money someone earns etc  (Some families in the ghettos have been on welfare all their lives. | People on high salaries should pay more tax.) 12 informal used to say that someone takes a particular drug or medicine  (Since she's been on Prozac she's been a different person.) 13 on the radio/telephone using a radio or telephone  (Shut up! I'm on the phone.) 14 on a trip/journey etc during a trip, journey etc  (I met several people on the voyage. | On my way to work the car broke down.) 15 used to say what has been used to do something  (Phil had torn his shirt on a nail. | It's amazing what you can do on these new word processors.) 16 formal immediately after something has happened or after someone has done something  (on doing sth)  (On hearing the news of the air attack most foreigners headed for the border. | on arrival/sb's return etc)  (On arrival at reception, guests should sign the visitors' book. | on sth)  (On the general's command, all soldiers must salute.) 17 used to say that someone is a member of a team, organization etc  (What team did you say your boyfriend was on?) 18 compared with another person or thing  (This essay is a definite improvement on your last one. | Sales are 10% up on last year.) 19 have/carry etc sth on you informal to have a particular thing in your pocket, your bag etc  (How much cash do you have on you?) 20 spoken used to say that someone will pay for something such as a drink, a meal etc  (Drinks are on Harold!) 21 informal if a machine stops, breaks etc on you, it stops or breaks while you are using it  (Suddenly the telephone went dead on me.) ~2 adj, adv 1 used to say that someone continues to do something or something continues to happen, without stopping  (play/read/talk etc on (=to continue playing, reading etc))  (Both teams managed to play on into overtime, despite the blistering heat.) carry/keep/go on etc doing sth  (If you keep on eating like that you'll need to diet. | carry/keep/go on etc)  (Carry on. You're doing very well.) 2 if you move, walk etc on, you move forward to a particular place  (If you walk on a little, you can see the coast. | You can have your letters sent on to you at your new address. | straight on)  (Keep straight on and turn left at the bank.) 3 used to say that something happens at a time that is before or after another time  (earlier/later on)  (Later on we learned that he got back to France safely. | from then on/from that day on etc)  (From that moment on I never believed a word she told me.) 4 if you have something on, you are wearing it  (Put your coat on. It's freezing outside. | The poor child had absolutely nothing on.) 5 in a bus, train, aircraft etc  (The bus stopped and everyone rushed to get on.) 6 if a machine, light etc is on, it is operating  (Who left the hot water faucet on? | The TV's on but nobody seems to be watching it.)  (- opposite off1 (4)) 7 if a film, TV programme etc is on, it is being broadcast or shown at a theatre  (That new sitcom is on tonight.) 8 if an event is on, it is happening or will still happen  (There's a jazz festival on in Vancouver this week. | Are you sure the party's on for tonight?) 9 have a lot on informal to be very busy  (We don't have much on at the moment. I could see you tomorrow.) 10 be on at sb informal to keep asking someone to do something, so that they become annoyed  (Mildred's been on at him to fix that cupboard for weeks now.) 11 be/go on about sth informal BrE to keep talking about something, in a way that is boring  (Will you stop going on about that goal! It was definitely a penalty.) 12 on and off also off and on if you do something during a period of time on and off, you do it for several short periods in that time but not continually  (He's been smoking for 10 years now, on and off.) 13 it's not on spoken BrE used to say that you do not think something is socially acceptable or reasonable  (It's not on, is it? Leaving your children alone like that.) 14 head on/full on if two things hit each other head on, they hit the front part of each other, usually very hard  (Both cars skidded, crashing head on at 80 miles an hour.) 15 if an actor is on, they are performing  (You're on in two minutes.)