- near or next to.
- The mailbox is by the bus stop.
- at some time before (the given time).
- Be back by ten o'clock!
- if something is done by somebody, it is done through their action
- The matter was decided by the chairman.
- The boat was swamped by the water.
- He was protected by his body armour.
- if something is created by somebody, they are the creator, author, etc.
- There are many well-known plays by William Shakespeare.
- shows how someone does something
- I avoided the guards by moving only when they weren't looking.
- using the rules or logic of.
- I sorted the items by category.
- with a change of. In this case, by shows how much something has changed.
- Our stock is up by ten percent.
- shows how slowly, or how quickly, someone does something (used in the form "X by X" or "by Xs")
- We went through the book page by page.
- We crawled forward by inches.
- When measuring the width and depth of something, by is used between the lengths of the two sides.
- The window is 45cm by 60cm.
- If you multiply by , you multiply × .
- Five multiplied by seven is 35.
- If you divide by , you find how many s are in .
- 35 divided by seven is five.