1US A linguistic feature peculiar to a particular county.
In later use only with preceding name specifying the county.
2Especially with reference to Ireland and Irish-American communities: attachment or loyalty to one's own county, its institutions, interests, etc., especially as considered more important than those of the nation or state of which it is a part. Now chiefly historical.
Mid 19th century; earliest use found in Lady's Book. From county + -ism.