Lewis Short
Matrae | Matres | Matronae (noun F) : (
* Dat. plur. MATRABVS, for Matris, Inscr. Grut. 29, 1), or , more freq. , the protecting goddesses of a country, city, or place: MATRIS AVGVSTIS D. D.,Inscr. Grut. 90, 1; so ib. 2 sq.
Charlton T. Lewis, Charles Short, A Latin Dictionary