The "Paraskevi" part is indeed a later addition; it became the word for "Friday" (replacing a simple "sixth day") because that's what it's called in the Greek Bible. It means "preparation" (specifically for the Sabbath--the day when you had to get the meals ready, do anything that required walking farther than the permitted "Sabbath journey," etc.

Last year's thread on the Bulgarian icons, some may recall, included that question about St Petka, which is a nickname for St Paraskevi--there are several saints by that name.

Stephen