Word Study pre + warm = prewarm (warm before-hand) dis + believe = disbelieve (not believe) A prefix is a syllable that can be added to the beginning of a word to form a word with a different meaning. The prefix pre often means "in advance" or "before-hand." The prefix dis often means "not." Read the definitions below. Add a prefix to each word in heavy type to make a new word with the stated meaning. Write the new word. 11. not approve: ___approve 12. not agree: agree 13. before history: history 14. before the flight: ___ flight​