The northern region of Númenor (UT/165), a combination of the prefixal form foro- of formen “north” and the plural of the suffix -sta “land”.
Quenya
Forostar
northlands
forostar
place name. Northlands
-sta
northlands
-sta (2) ending occurring in the names of certain lands(VT43:15), e.g. the Forostar or "Northlands" of Númenor (UT:165)
Forostar place-name, the "Northlands" of Númenor (UT:165)