1 a : touching and being supported by the top surface of (something)
▪ The book is (lying) on the table. ▪ There is a lot of frosting on the cake.
b : to a position that is supported by (something)
▪ You can get on [=onto] the horse as soon as we've put the saddle on it. ▪ I climbed out on [=onto] the roof.
c — used to indicate the part or object by which someone or something is supported ▪ How long can you stand on one foot? ▪ He stood on the stool. ▪ He was on his hands and knees looking for her earring. 2 — used to say that something is attached to something ▪ He hung the painting on the wall. ▪ Apples hung on the branches. 3 — used to indicate where someone or something is hit or touched ▪ I bumped my head on a low branch. ▪ He slapped me on the hand. ▪ She kissed him on the cheek. 4 a — used to indicate the surface or part where something is seen or located ▪ There are marks on the wall. ▪ I have a cut on my finger.
b — used to say that something (such as jewelry) is being worn by someone ▪ the ring on her finger 5 : near or close to (something or someone)
▪ a village on [=by] the sea 6 — used to indicate the location or position of something or someone ▪ Our house is on the left. ▪ There is a garden on the side of the house. ▪ We saw cows and chickens on the farm. ▪ He lives on Main Street. ▪ on page 102 in/of the book ▪ Which side is it on? 7 — used to indicate the time when something happened or will happen ▪ We met on July 24th. ▪ On my way home [=while I was going home], I saw a car accident. ▪ (formal) On the morning of July 24th, the suspect left his house at 8:15 a.m. ▪ I would like the report on or before July 24th. ▪ The TV station gives news every hour on the hour. [=at 6:00, 7:00, 8:00, etc.] ▪ The project was finished on schedule/time. [=when it was supposed to be finished] 8 : immediately after (something)
▪ What was your first reaction on hearing the news? [=when you heard the news] ▪ You'll be required to pay on delivery of the package. [=when the package is delivered] 9 — used to indicate the subject of something ▪ a book on [=about] North American birds ▪ a discussion on current events ▪ Let's reflect on [=upon] the poem for a moment. ▪ a test on parts of speech 10 a — used to indicate the device or instrument that is used to do something ▪ He played a couple songs on the piano. ▪ He cut his foot on a piece of broken glass.
b — used to say that someone is using a telephone, computer, etc. ▪ They talked on the phone for hours. ▪ She was on the phone when I went to her office. ▪ He has been on the computer all night.
c — used to describe the device, system, etc., that is used for seeing something, hearing something, etc. ▪ It's the best show on television. ▪ I heard that song on the radio. ▪ the display on the computer screen ▪ a Web site on the Internet ▪ I have the movie on DVD. 11 — used to indicate a source of something (such as money, food, information, or energy) ▪ She lives on a small salary. ▪ The family lives on welfare. ▪ They make their living on [=off] tourism. ▪ They profited on [=from] the sale of the house. ▪ The animal feeds on insects. ▪ I lived on cereal [=I ate a lot of cereal regularly] in my college years. ▪ The machine runs on diesel fuel. ▪ The story is based on fact. 12 — used to indicate the vehicle or animal by which someone or something is moved from one place to another ▪ I sometimes go to work on a bus. [=I sometimes take a bus to get to work] ▪ Have you ever ridden on a horse? 13 — used to say that you have something in your possession at a particular time ▪ I only have $10 on me. ▪ He had a knife on him. 14 — used to indicate the state of something ▪ The house is on fire! ▪ House sales are on the rise. [=are rising] ▪ All shoes are on sale. 15 — used to indicate an activity that someone did or is now doing ▪ She did well on the exam/test. ▪ The band is currently on tour. ▪ He is off/away on a trip/vacation. ▪ She is on a diet. ▪ The officers are on duty. 16 — used to indicate something (such as a medicine or drug) that a person or animal is using ▪ He used to be on drugs, but he's off them now. ▪ (informal) What (drugs) is she on? ▪ They put the dog on antibiotics. 17 — used to indicate the person or thing that is responsible for something ▪ The drinks are on me. [=I will pay for the drinks] ▪ They blamed it on me. [=they said it was my fault] 18 a — used to indicate the person or thing that something is directed toward ▪ The deadline was creeping up on us. [=the deadline was getting closer] ▪ an attack on religion ▪ He is working on [=at] his skiing. ▪ They are still working on the problem. ▪ They made a down payment on the house. ▪ He pulled a gun on me. ▪ He turned his back on her and walked away. ▪ a ban on smoking ▪ Her eyes were on the road. [=she was watching the road]
b — used to say that someone has been affected by something ▪ The crops died on them. ▪ Her husband walked out on her. 19 — used after an adjective to indicate the thing that a statement relates to ▪ I am short on cash. [=I don't have much cash] ▪ Opinions are divided on this issue. ▪ (Brit) Sales are up on last year's but down on those of previous years. 20 : as stated or shown by (someone or something)
▪ I have it on good authority [=a trustworthy person has told me] that the company will be relocating. ▪ (Brit) On [=according to] these estimates, we'll be out of debt soon. 21 — used to indicate that someone or something is included as part of a team, list, etc. ▪ She served on the jury/committee/board. ▪ He is on the team. ▪ That dish is no longer on the menu. ▪ His name was on the list. 22 — used to say that someone or something has an advantage ▪ She has three inches in height on me. [=she is three inches taller than I am] ▪ The team has a 3-game lead on last year's champions. ▪ She is very talented but has nothing on [=has no advantage over] her brother who is an even better singer. 23 chiefly US — used to say that someone is playing or performing well ▪ He is on his game. [=he is playing very well]