Merriam-Webster Collegiate Dictionary - wherewith

 I. pronoun  Date: 13th century archaic that with or by which — used with an infinitive so shall I have ~ to answer him — Psalms 119:42 (Authorized Version)  II. adverb  Date: 13th century obsolete with what ~ shall it be salted — Matthew 5:13 (Authorized Version)  III. conjunction  Date: 14th century with or by means of which metal tools ~ to break ground — Russell Lord