A prefix is a word part that is added to the beginning of a word to change its meaning.
* Sub- means "under" or "below" (e.g., submarine, submerge).
* Ante- means "before" or "in front of" (e.g., antecedent, antebellum).
* Con- has several meanings, including "with," "together," and "against" (e.g., connect, coexist, confront).