The name Demelza is a girl's name of Cornish origin meaning "fort on the hill". Demelza and is often added to lists like Cornish Baby Names and discussed in our forums with posts like "drop two add one: Girls!".
From the experts:
Complex and challenging modern Cornish name derived from a place name. The given name began to be used in the U.K. in the 1950s via the serialization on British TV of the Poldark novels of Winston Graham, whose heroine was named Demelza.