What is "dunglass"

Dunglass is a hamlet in East Lothian, Scotland, lying east of the Lammermuir Hills on the North Sea coast, within the parish of Oldhamstocks. It has a 15th-century collegiate church, now in the care of Historic Scotland. Dunglass is the birthplace of Sir James Hall, an 18th-century Scottish geologist and geophysicist. The name Dunglass comes from the Brittonic for "grey-green hill".