Definition of prefix

• v. t. - To put or fix before, or at the beginning of, another thing; as, to prefix a syllable to a word, or a condition to an agreement.
• v. t. - To set or appoint beforehand; to settle or establish antecedently.
• n. - That which is prefixed; esp., one or more letters or syllables combined or united with the beginning of a word to modify its signification; as, pre- in prefix, con- in conjure.