1. Means of transportation or action:
* "I traveled by train." (Means of transportation)
* "He was injured by a falling rock." (Means of action)
2. Agent or person responsible:
* "The house was built by John." (Person responsible)
* "The painting was created by a famous artist." (Agent responsible)
3. Position or location:
* "Stand by the window." (Location)
* "He lives by the beach." (Position)
4. Near or close to:
* "The store is by the post office." (Proximity)
* "I'll be back by noon." (Close to a specific time)
5. At the latest:
* "You must submit your application by Friday." (Deadline)
* "The train leaves at 10:00, but you can board by 9:45." (Latest time for action)
6. Comparison or contrast:
* "He is tall by my standards." (Comparison)
* "By comparison, this method is much faster." (Contrast)
7. Multiplied by:
* "Three by four equals twelve." (Multiplication)
8. According to:
* "By his own admission, he made a mistake." (According to someone's own statement)
* "By all accounts, the concert was a success." (According to various sources)
9. Through or along:
* "He walked by the river." (Movement along a path)
* "The mailman delivers the mail by car." (Means of movement)
10. On behalf of:
* "I'm writing to you by request of my boss." (On someone else's behalf)
It's important to look at the context of the sentence to understand which meaning of "by" is being used.