Eon de Beaumont, Charles d', the “Chevalier d'Eon,” a noted French diplomatist, born at Tonnerre, Burgundy; notorious as having, while on secret missions, adopted a woman's dress for purposes of disguise; was ambassador at the English Court, but degraded and recalled by Louis XVI., and condemned to wear feminine garb till the close of his life; died in destitution, when the popular doubt as to his real sex was set at rest (1728‒1810).
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Eon * Eos