1911 Encyclopædia Britannica, Volume 27… (1911)
“ UNCLE, the brother of a person's father or mother, also the husband of one's aunt (i.e. the sister of a father or mother) . The French oncle, which appears in Anglo-French as uncle, comes from a Late Latin unculus, a shortened form of the Latin avanculus, a maternal uncle, the brother of one's mother. ”
