VERNAC'ULAR, a. [L. vernaculus, born in one's house, from verns, a servant.]1. Native; belonging to the country of one's birth. English is our vernacular language. The vernacular idiom is seldom perfectly acquired by foreigners.2. Native; belonging to the person by birth or nature.A vernacular disease, is one which prevails in a particular country or district; more generally called endemic.