Lewis Short
(adjective) : petrōsus, a, um, 1. petra
* Full of rocks, rocky (post-Aug.): loca,Plin. 9, 31, 50, § 96.—Subst.: petrōsa, ōrum, n., rocky places: maritima,Plin. 26, 8, 29, § 46; Ambros. Laps. Virg. 7, 29: aliud cecidit super petrosa,Vulg. Marc. 4, 5; id. Matt. 13, 5.
Charlton T. Lewis, Charles Short, A Latin Dictionary