Need some help with the prepositions AT and BY...

AT: used to say exactly where something or someone is, or where something happens
BY: beside or near something.

1. She stood AT the window
2. She stood BY the window

3. Who is AT the door?
4. Who is BY the door?

5. I left him AT the sledge
6. I left him BY the sledge

7. He was standing AT the bed.
8. He was standing BY the bed.

Is AT/BY interchangable in this context? If not, what are the differences?
And if only one of them is right, why is it so?


I'm a learner from Japan. I also have trouble in choosing this sort of preposition. If you don't mind, let me try to answer. Maybe I will make some mistakes, but you can be sure any of our teachers corrects me in such a case.

1. She stood AT/BY the window
2. He was standing BY/AT the bed.
'Stand at X' and 'stand by X' both can mean 'stand close to X', and they are mostly interchangeable. But when the subject is practically in contact with X, 'at X' will be better.

3. Who is AT the door?
'Be at the door' is kind of an idiomatic phrase.

4. I left him IN/ON the sledge.
If you mean 'inside of the sledge', should be IN or ON.
I think in the sentences with "at," there is more a sense that the person is near the object for a reson related to its intended purpose. If he is "at the door" he is probably waiting to be let in; if she is "at the window," she is probably looking through the window. If he is "by the door" and she is "by the window," it could just be by chance, they are not necessarily paying any attention to the door or the window. It's a subtle difference; in many cases the words would be interchangeable.
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I agree with you completely. Someone standing at the sink is probably washing dishes. Someone standing by the sink is probably just talking to the one washing the dishes! Similarly, you can place a bag of just purchased groceries by the sink, but you would hardly say that you placed them at the sink.

Hello Khoff and CJ

Thank you for the nice tip. Then what is the difference between 'stand by the bed' and 'stand at the bed'?

Thanks, Jim! Check out the "rock and stone" thread - do you agree with me there?

Paco - I don't have a clear feeling for "at the bed"/"by the bed" - I don't think we talk about people standing near beds often enough for much of a distinction to have emerged! I guess you could make the same distinction - if you are standing "by the bed," you might just be looking out the window or setting your alarm clock, but if you are standing "at the bed" you are probably watching someone sleep. But I don;t feel the distinction as strongly as in the earlier examples.

Maybe it's because if you are really using the bed for its intended purpose you are neither at nor by the bed, but in it. Here I think you can make the distinction between "in bed" (resting, sleeping, or engaging in other activities that usually occur in beds) and "in the bed" (specifying location only, not purpose). "She was in bed and was almost asleep when she noticed there was a spider in the bed."
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Hello Khoff

Thank you for the answer. Actually the use of 'stand at' is rare compared with that of 'stand by' (the ratio is about 1 to 10). I'll understand that 'stand at' is 'stand near with some purpose' and 'stand by' is 'stand near without any purpose'.
She was deathly ill. The doctor leaned over her to see if there were any signs of life.
Her family had all gathered at (the foot of) the bed.

In my opinion, "at" suggests more involvement and interest than "by".