A prefix is a word part that is added to the beginning of a base word to create a new word with a different meaning. It can change the word's overall meaning or create a word with a different grammatical function. For example, the prefix "un-" added to the base word "happy" creates the word "unhappy," meaning not happy. The prefix "pre-" added to the base word "fix" creates the word "prefix," meaning something added before.
