petrous

adjective

1. Anatomy. noting or pertaining to the hard dense portion of the temporal bone, containing the internal auditory organs; petrosal.
2. like stone, especially in hardness; stony; rocky.

adjective

1. anatomy denoting the dense part of the temporal bone that surrounds the inner ear
2. rare like rock or stone

adj.1540s, from Middle French petreux, from Latin petrosus “stony,” from petra “rock,” from Greek petra “rock, cliff, ledge, shelf of rock, rocky ridge,” of uncertain origin. Possibly from PIE root *per- “to lead, pass over,” if the original meaning is “bedrock” and the notion is “what one comes through to” [Watkins]. adj.

1. Of stony hardness.
2. Of or relating to the dense hard portion of the temporal bone that forms a protective case for the inner ear.