(lɑ̃g dɔˈil, ˈdɔ i, ˈdɔɪl) n. the Romance speech of medieval N France; medieval French. [1695–1705; < French: language of oïl, i.e., speech in which oïl is used for “yes” (Old French o il this he (did) < Latin hōc ille; compare French oui)]ThesaurusSeeLangue d'oil