#4073 πέτρα petra {pet'-ra}

 from the same as G4074; TDNT - 6:95,834; n f

—Greek Word Study (Transliteration-Pronunciation Etymology & Grammar)

 1) a rock, cliff or ledge
    1a) a projecting rock, crag, rocky ground
    1b) a rock, a large stone
    1c) metaph. a man like a rock, by reason of his firmness and
        strength of soul

—Thayer's (New Testament Greek-English Lexicon)

—Strong's (Greek Dictionary of the New Testament)

—NAS Exhaustive Concordance of the Bible with Hebrew-Aramaic and Greek Dictionaries

 AV - rock 16; 16

—Exhaustive Concordance (KJV Translation Frequency & Location)