πέτρα
πέτρα
.πέτρα, Ionic and Epic πέτρη, ἡ,
a rock, a ledge or shelf of rock, Od.
a rock, i. e. a rocky peak or ridge, Hom.; π. σύνδρομοι, ξυμπληγάδες, of the rocky islets of the Bosporus, Pind., Eur.; π. δίλοφος, of Parnassus, Soph.—Properly, πέτρα is a fixed rock, πέτρος a stone: in Od. 9, πέτραι are masses of live rock torn up by giants.
πέτρη γλαφυρή a hollow rock, i. e. a cave, Il.; δίστομος π. a cave in the rock with a double entrance, Soph.
proverbial usages:—on οὐκ ἀπὸ δρυὸς οὐδʼ ἀπὸ πέτρης, v. δρῦς:— as a symbol of firmness, ὁ δʼ ἐστάθη ἠύτε πέτρη Od.; of hardheartedness, ἐκ πέτρας εἰργασμένος Aesch.