The preposition is pronounced /baɪ/. The adverb is pronounced /baɪ/.
Frequency: The word is one of the 700 most common words in English.
Note: In addition to the uses shown below, 'by' is used in phrasal verbs such as ‘abide by’, ‘put by’, and ‘stand by’.
1.
If something is done by a person or thing, that person or thing does it.
The feast was served by his mother and sisters...
I was amazed by their discourtesy and lack of professionalism...
The town has been under attack by rebel groups for a week now.
PREP
2.
If you say that something such as a book, a piece of music, or a painting is by a particular person, you mean that this person wrote it or created it.
...a painting by Van Gogh...
‘Jacob’s Ladder’, the newest film by Adrian Lyne, is a post-Vietnam horror story.
PREP
3.
If you do something by a particular means, you do it using that thing.
We’ll be travelling by car.
...dinners by candlelight.
PREP
4.
If you achieve one thing by doing another thing, your action enables you to achieve the first thing.
Make the sauce by boiling the cream and stock together in a pan...
The all-female yacht crew made history by becoming the first to sail round the world...
By using the air ambulance to transport patients between hospitals, they can save up to £15,000 per patient.
PREP : PREP -ing
5.
You use by in phrases such as ‘by chance’ or ‘by accident’ to indicate whether or not an event was planned.
I met him by chance out walking yesterday...
He opened Ingrid’s letter by mistake...
Whether by design or accident his timing was perfect.
PREP
6.
If someone is a particular type of person by nature, by profession, or by birth, they are that type of person because of their nature, their profession, or the family they were born into.
I am certainly lucky to have a kind wife who is loving by nature...
She’s a nurse by profession and now runs a counselling service for women...
Her parents were in fact American by birth.
PREP : adj / n PREP n
7.
If something must be done by law, it happens according to the law. If something is the case by particular standards, it is the case according to the standards.
Pharmacists are required by law to give the medicine prescribed by the doctor.
...evening wear that was discreet by his standards.
PREP
8.
If you say what someone means by a particular word or expression, you are saying what they intend the word or expression to refer to.
Stella knew what he meant by ‘start again’...
‘You’re unbelievably lucky’—‘What do you mean by that?’
PREP
9.
If you hold someone or something by a particular part of them, you hold that part.
He caught her by the shoulder and turned her around...
She was led by the arm to a small room at the far end of the corridor...
He picked up the photocopy by one corner and put it in his wallet.
PREP
10.
Someone or something that is by something else is beside it and close to it.
Judith was sitting in a rocking-chair by the window...
Felicity Maxwell stood by the bar and ordered a glass of wine...
Emma was by the door.
PREP
•
By is also an adverb.
Large numbers of security police stood by.
ADV : ADV after v
11.
If a person or vehicle goes by you, they move past you without stopping.
A few cars passed close by me...
He kept walking and passed by me on his side of the street.
PREP : v PREP n
•
By is also an adverb.
The bomb went off as a police patrol went by.
ADV : ADV after v
12.
If you stop by a place, you visit it for a short time.
We had made arrangements to stop by her house in Pacific Grove...
PREP
•
By is also an adverb.
I’ll stop by after dinner and we’ll have that talk.
ADV : ADV after v
13.
If something happens by a particular time, it happens at or before that time.
By eight o’clock he had arrived at my hotel...
We all knew by then that the affair was practically over.
PREP
14.
If you do something by day, you do it during the day. If you do it by night, you do it during the night.
By day a woman could safely walk the streets, but at night the pavements became dangerous...
She had no wish to hurry alone through the streets of London by night.
PREP
15.
In arithmetic, you use by before the second number in a multiplication or division sum.
...an apparent annual rate of 22.8 per cent (1.9 multiplied by 12)...
230cm divided by 22cm is 10.45cm.
PREP : PREP num
16.
You use by to talk about measurements of area. For example, if a room is twenty feet by fourteen feet, it measures twenty feet in one direction and fourteen feet in the other direction.
Three prisoners were sharing one small cell 3 metres by 2 metres.
PREP : PREP num
17.
If something increases or decreases by a particular amount, that amount is gained or lost.
Violent crime has increased by 10 percent since last year...
Their pay has been cut by one-third.
PREP : PREP amount
18.
Things that are made or sold by the million or by the dozen are made or sold in those quantities.
Parcels arrived by the dozen from America...
Liberty fabrics, both for furnishing and for dress-making, are sold by the metre.
PREP : PREP the n
19.
You use by in expressions such as ‘minute by minute’ and ‘drop by drop’ to talk about things that happen gradually, not all at once.
His father began to lose his memory bit by bit, becoming increasingly forgetful.
PREP : n PREP n
20.
If you are by yourself , you are alone.
...a dark-haired man sitting by himself in a corner.
= alone
PHRASE : PHR after v
21.
If you do something by yourself , you succeed in doing it without anyone helping you.
I didn’t know if I could raise a child by myself.
PHRASE : PHR after v