ver ‧ nac ‧ u ‧ lar /vəˈnækjələ, vəˈnækjʊlə $ vərˈnækjələr/ BrE AmE noun [countable usually singular]
[ Date: 1600-1700 ; Language: Latin ; Origin: vernaculus 'born in a place' , from verna 'slave born in his or her owner's house' ]
1 . a form of a language that ordinary people use, especially one that is not the official language
in the vernacular
Galileo wrote in the vernacular to reach a larger audience.
He lapsed into the local vernacular (=language spoken in a particular area) .
2 . a style of building, music, art etc that is suitable for ordinary people
—vernacular adjective :
vernacular American speech
vernacular architecture