Prefix

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.

To set or appoint beforehand; to settle or establish antecedently.

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.

an affix that is added in front of the word

attach a prefix to; "prefixed words"