Meaning "before," "in front of," "early" or "prior to," the prefix "pre-" originates from the Latin "prae," which means "before" or "in front." According to Dictionary.com, even "pre-" in the word prefix itself means "in front of" since it sits in front of a word to give it new meaning.
Examples of words containing the prefix "pre-" are preschool, which is an early form of school; predetermine, which means to decide ahead of time; and preadmission, which means letting in early. Precautions are preventative steps taken ahead of time and prejudice is the process of passing judgment before knowing the facts. When something is prepaid, it is paid for in advance.