The definition of could've is something that potentially might have happened if it weren't for another alternative.
An example of could've is for a student to say that he had the potential to do his homework instead of choosing to go to the basketball game.
- Used to show there was possibility of something happening in the past, but it did not happen.
- We could've missed the bus, but we just caught it.
could + -'ve
- You could've told Damian you were in danger.
- No one else could've done it.
- I could've guessed Darian would fall for you the way he followed you around.
- You could've checked up on me at any point.
- It could've been worse.