by
The book is by the window.
The book is located beside the window.
indicating location next to or beside something
She sat by the fireplace.
She was seated next to the fireplace.
The store is by the bank.
The store is located near the bank.
Commonly used to describe physical proximity.
indicating the agent in a passive construction
The book was written by Shakespeare.
Shakespeare is the author of the book.
The cake was baked by my mom.
My mom is the one who baked the cake.
Used to show who performed an action in passive voice sentences.
not later than; before
Please finish by 5 PM.
You should complete the task no later than 5 PM.
I’ll be there by noon.
I will arrive before or at noon.
Indicates a deadline or time limit.
through the agency or means of
We traveled by train.
We used a train to travel.
She succeeded by hard work.
She achieved success through hard work.
Indicates the method or means by which something is done.
to the extent of (used with measurements)
The river is 100 meters wide by 50 meters deep.
The river's width is 100 meters and its depth is 50 meters.
Used to specify dimensions or quantities.
Collocations
Related Phrases
Pro Tip
Distinguishing 'by' in passive voice
In passive sentences, 'by' introduces the doer of the action. Example: 'The letter was written by John.' Here, 'John' is the agent performing the action of writing.
Gold Rule
Use 'by' for deadlines
When indicating a deadline, 'by' means 'not later than'. Example: 'Submit your homework by Friday.'
Use 'by' for means of transport
When referring to transportation, 'by' is used without articles. Example: 'We traveled by car.' (Not 'by the car' or 'by a car')
Word Origin
Old English 'bī', of Germanic origin; related to Dutch 'bij' and German 'bei'. Originally meant 'near' or 'by the side of'.
Usage Notes
The word 'by' is highly versatile and functions as a preposition, adverb, or adjective in different contexts. It is often confused with 'buy' (to purchase) or 'bye' (farewell), but 'by' serves grammatical roles in sentences.