Lewis Short
(adjective) : Petrĕus, a, um, 1. petra or Petrus
* Petrean (eccl. Lat.): istae spinae, Petra et Petro transeunte, petreis pedibus tritae sunt, of rock or stone, or pertaining to the Apostle Peter, Aug. Serm. 297, 2 fin.
Charlton T. Lewis, Charles Short, A Latin Dictionary