Formally
Pronunciation : Form"al*ly
Part of Speech : adv.
Definition : Defn: In a formal manner; essentially; characteristically; expressly; regularly; ceremoniously; precisely. That which formally makes this [charity] a Christian grace, is the spring from which it flows. Smalridge. You and your followers do stand formally divided against the authorized guides of the church and rest of the people. Hooker.
Source : Webster's Unabridged Dictionary, 1913
Merriam-Webster's Everyday Language Reference Set: Includes: The Merriam-Webster Dictionary, The Merriam-Webster Thesaurus, and The Merriam-Webster Vocabulary Builder