28 ADV [ADV after v] You use on to say that someone is continuing to do something. □ They walked on in silence for a while. □ If the examination shows your company enjoys basically good health, read on. □ He happened to be in England when the war broke out and he just stayed on.
29 ADV [be ADV , ADV after v] If you say that someone goes on at you, you mean that they continually criticize you, complain to you, or ask you to do something. □ [+ at ] She's been on at me for weeks to show her round the stables. □ [+ at ] He used to keep on at me about the need to win.
30 ADV [from n ADV ] You use on in expressions such as from now on and from then on to indicate that something starts to happen at the time mentioned and continues to happen afterwards. □ Perhaps it would be best not to see much of you from now on. □ We can expect trouble from this moment on.
31 ADV [adv ADV ] You often use on after the adverbs 'early', 'late', 'far', and their comparative forms, especially at the beginning or end of a sentence, or before a preposition. □ The market square is a riot of colour and animation from early on in the morning. □ Later on I learned how to read music. □ The pub where I had arranged to meet Nobby was a good five minutes walk further on.
32 PREP Someone who is on a drug takes it regularly. □ She was on antibiotics for an eye infection that wouldn't go away. □ Many of the elderly are on medication.
33 PREP If you live on a particular kind of food, you eat it. If a machine runs on a particular kind of power or fuel, it uses it in order to function. □ The caterpillars feed on a wide range of trees, shrubs and plants. □ He lived on a diet of water and tinned fish. □ …making and selling vehicles that run on batteries or fuel-cells.
34 PREP If you are on a particular income, that is the income that you have. □ He's on three hundred a week. □ You won't be rich as an MP, but you'll have enough to live on.
35 PREP Taxes or profits that are obtained from something are referred to as taxes or profits on it. □ …a general strike to protest a tax on food and medicine last week. □ The Church was to receive a cut of the profits on every record sold.
36 PREP When you buy something or pay for something, you spend money on it. □ I resolved not to waste money on a hotel. □ He spent more on feeding the dog than he spent on feeding himself. □ More money should be spent on education and housing.
37 PREP When you spend time or energy on a particular activity, you spend time or energy doing it. □ People complain about how children spend so much time on computer games. □ …the opportunity to concentrate more time and energy on America's domestic agenda.
38 PHRASE If you say that something is not on or is just not on , you mean that it is unacceptable or impossible. [mainly BRIT , INFORMAL ] □ We shouldn't use the police in that way. It's just not on.
39 PHRASE If you say that something happens on and on , you mean that it continues to happen for a very long time. □ …designers, builders, fitters–the list goes on and on. □ Lobell drove on and on through the dense and blowing snow. □ …a desert of ice stretching on and on.
40 PHRASE If you ask someone what they are on about or what they are going on about , you are puzzled because you cannot understand what they are talking about. [BRIT , INFORMAL ] □ What on earth are you going on about? □ Honest, Kate, I don't know what you're on about.
41 PHRASE If you say that someone knows what they are on about , you are confident that what they are saying is true or makes sense, for example because they are an expert. [BRIT , INFORMAL ] □ It looks like he knows what he's on about.
42 PHRASE If someone has something on you, they have evidence that you have done something wrong or bad. If they have nothing on you, they cannot prove that you have done anything wrong or bad. [INFORMAL ] □ Secret services now had something on her if they needed it. □ You've got nothing on me and you know it. Your theory would never stand up in a court of law.
43 on behalf of → see behalf
44 on and off → see off
45 and so on → see so
46 on top of → see top
once ◆◆◆ /wʌ ns/
1 ADV [ADV with v] If something happens once , it happens one time only. □ I met Wilma once, briefly. □ Since that evening I haven't once slept through the night. □ Mary had only been to Manchester once before. ● PRON Once is also a pronoun. □ 'Have they been to visit you yet?'—'Just the once, yeah.' □ Listen to us, if only this once.
2 ADV You use once with 'a' and words like 'day', 'week', and 'month' to indicate that something happens regularly, one time in each day, week, or month. □ Lung cells die and are replaced about once a week. □ We arranged a special social event once a year to which we invited our major customers.
3 ADV [ADV with v, ADV with be ] If something was once true, it was true at some time in the past, but is no longer true. □ The culture minister once ran a theatre. □ I lived there once myself, before I got married. □ The house where she lives was once the village post office. □ My memory isn't as good as it once was.