Here are some examples:
* Prepaid: Paid before receiving the goods or services.
* Premature: Happening or done before the usual or expected time.
* Prehistoric: Belonging to a period of time before recorded history.
* Preconception: An opinion or belief formed before having sufficient evidence.
* Preview: A showing of a film, play, or other work before it is released to the public.
Essentially, "pre-" indicates something that happens prior to another event or action.