An example of the pre prefix is preschool or school you attend before you officially start school.
An example of the pre prefix is preheat, or to heat an oven before you put something in to cook.
Origin of pre
From Webster's New World College Dictionary, 5th Edition
- Middle English from Old French from Latin prae- from prae before, in front per1 in Indo-European roots
From American Heritage Dictionary of the English Language, 5th Edition
- From Latin prae (“in front of"), see pre-