Quick Definition
πέτρα, ας, ἡ n.f. rock
Strong's Definition
feminine of the same as 4074; a (mass of) rock (literally or figuratively)
KJV Usage: rock
UBS Dictionary of the Greek New Testament
noun, f. | -ας | πετρῶδες
2.21 · Natural Substances · Earth, Mud, Sand, Rock
rock, bedrock bedrock (possibly covered with a thin layer of soil), rocky crags, or mountain ledges, in contrast with separate pieces of rock normally referred to as λίθος[a] (see 2.23) ὁμοιωθήσεται ἀνδρὶ φρονίμῳ, ὅστις ᾠκοδόμησεν αὐτοῦ τὴν οἰκίαν ἐπὶ τὴν πέτραν ‘he is like a wise man who built his house on bedrock’ MAT 7:24; ἔθηκεν αὐτὸν ἐν μνημείῳ ὅ ἦν λελατομημένον ἐκ πέτρας ‘they then put him in a grave which had been hewn from rock’ MRK 15:46; λέγουσιν τοῖς ὄρεσιν καὶ ταῖς πέτραις, Πέσετε ἐφ ̓ ἡμᾶς ‘they said to the mountains and to the rock cliffs, Fall on us’ REV 6:16. In these three contexts πέτρα must be translated in some languages by three quite different terms. Bedrock, that is to say, the rock which lies horizontally and often just below the surface, may be referred to by one term, while rock with an exposed face into which a tomb could be hewn would be quite different. Similarly, the rocks which would be called upon to fall upon people would be rendered by a term referring to ‘cliffs’ or ‘precipices.’
In LUK 8:6 the term πέτρα in ἕτερον κατέπεσεν ἐπὶ τὴν πέτραν ‘other (seed) fell on rocky ground’ refers to bedrock which may be covered with a thin layer of soil. One may translate such an expression as ‘thin ground over rock’ or ‘just a little soil on top of rock.’
In those passages which involve a play on words with the name Πέτρος ‘Peter,’ πέτρα refers to bedrock, that is to say, the rock on which a foundation may be placed.
MAT 7:24 · MAT 7:25 · MAT 16:18 · MAT 27:51 · MAT 27:60 · MRK 15:46 · LUK 6:48 · LUK 8:6 · LUK 8:13 · ROM 9:33 · 1CO 10:4 · 1CO 10:4 · 1PE 2:8 · REV 6:15 · REV 6:16
1 ROM 9:33 · 1PE 2:8 In ROM 9:33 and 1PE 2:8 πέτρα occurs in parallelism with λίθος stone, as a quotation from ISA 8:14. On the basis of this usage one might argue that λίθος and πέτρα are completely synonymous, at least in this context. One would then have to describe πέτρα as having two different meanings, one rock and another stone. Parallelism, however, does not mean identity of meaning. In fact, parallelism (in contrast with tautology) normally implies slight differences of meaning in corresponding lexical items.
UBS Dictionary of the Greek New Testament © United Bible Societies, licensed CC BY-SA 4.0.
Thayer's Greek Lexicon
πέτρα, -as, ἡ, fr. Hom. down; Sept. for yd and Ἔχ; a rock, ledge, cliff’; a. prop.: Mt. vii. 24 sq. ; XXvii. 51,60; Mk. xv. 46; Lk. vi.48; 1 Co. x.4 (on which see πνευματικός, 3 a.) ; a projecting rock, crag, Rev. vi. 15sq.; rocky ground, Lk. viii. 6, 13. b. arock, large stone: Ro. ix. 33; 1 Pet. ii. 8 (7). c. metaph. a man like a rock, by reason of his firmness and strength of soul: Mt. xvi. 18 [some interpp. regard the distinction (generally observed in classic Greek ; see the Comm. and cf. Schmidt, Syn. ch. 51, §§ 4-6) between πέτρα, the massive living rock, and πέτρος, a detached but large fragment, as important for the correct understanding of this passage; others explain the different genders here as due first to the personal then to the material reference. Cf. Meyer, Keil, al.; Green, Crit. Note on Jn. i. 43].
Mounce Concise Greek Dictionary
πέτρα petra 15x
a rock, Mt. 7:24, 25; met. Rom. 9:33; 1 Pet. 2:8; crags, clefts, Rev. 6:15, 16; stony ground, Lk. 8:6, 13
Abbott-Smith Greek Lexicon
πέτρα, -ας, ἡ,
[in LXX chiefly for סֶלַע, צוּר;]
a rock, i.e. a mass of live rock as distinct from πέτρος, a detached stone or boulder: Mt 7:24, 25 27:51, 60, Mk 15:46, Lk 6:48 8:6, 13; of a hollow rock, a cave, Re 6:15, 16 (cf. Is 2:10, al.). Metaph., Mt 16:18 (on the meaning, v. Hort, Eccl., 16 ff., but cf. also ICC, in l.), I Co 10:4; = πέτρος, Ro 9:33, I Pe 2:8(LXX).†
Moulton & Milligan — Vocabulary of the Greek NT
πέτρα, “a rock’’: PSI IV. 4239 (iii/B.c.) λελατομεύκαμεν δὲ καὶ λίθους βασιλικοὺς ἐκ τῆς πέτρας, P Leid W** 86 (1i/iii A.D.) (=I. p. 149) 4(= at) πέτραι, καὶ τὰ ὄρη, καὶ ἣ θάλασσα. In PSI LV. 433 (B.C. 261-0) πέτρα is used rather of rocky ground, much like πετρώδης in Mt 13° αὐ, τὰ σκόρδα (‘‘garlic”) τὰ ἐπὶ τῆς πέτρας, 7 οὐκ ἐφυτεύθη οὖν ἐπὶ τῆς πέτρας ᾽Οασιτικά : cf. the similar use of πετραῖος in P Tebt I. 84.-8 (B.c. 118). For the catastrophic influence of the divine name we may cite the magic P Leid Vi 31 (iii/iv A.D.) (=II. p. 27) οὗ τὸ ὄνομα {od} ἡ γῆ ἀκούσασα ἐλεύσεται, ὃ ἅδης ἀκούων ταρόσσεται.. . . at πέτραι ἀκούσασαι ῥήγυνί -- νυν)ται : cf. Mt 2752. See also P Osl I. 1255 with the editor’s note.
Liddell-Scott-Jones — Greek-English Lexicon
πέτρα (petra) — rock. πέτρα, Ionic dialect and Epic dialect πέτρη, ἡ, rock; frequently of cliffs, ledges, etc. by the sea, λισσὴ αἰπεῖά τε εἰς ἅλα πέτρη [Refs 8th c.BC+]; χῶρος λεῖος πετράων free from rocks, of a beach,[Refs 8th c.BC+]; χοιρὰς π. [Refs 5th c.BC+]; also, rocky peak or ridge, αἰγίλιψ π. [Refs 8th c.BC+]; λιττὰς π. [Refs 6th c.BC+]; π. Λευκάς, Ὠλενίη, etc., [Refs 8th c.BC+]; π. σύνδρομοι, Συμπληγάδες, [Refs 5th c.BC+]; πρὸς πέτραις ὑψηλοκρήμνοις, of Caucasus, [Refs 4th c.BC+]; π. Δελφίς, π. δίλοφος, of Parnassus, [Refs 5th c.BC+]; π. Κεκροπία, of the Acropolis, [Refs 5th c.BC+]
2. π. γλαφυρή a hollow rock, i.e. a cave, [Refs 8th c.BC+]; σπέος κοιλῇ ὑπὸ π. [Refs 8th c.BC+]; δίστομος π. cave in the rock with a double entrance, [Refs 5th c.BC+]; κατηρεφεῖς αὐτῇ τῇ π. [Refs 5th c.BC+]; ἕως τῆς π. down to virgin rock, [NT+3rd c.BC+]
3. mass of rock or boulder, [Refs 8th c.BC+]
4. stone as material, π. λαρτία, Τηΐα, [Refs 3rd c.BC+], which is variant in X.[same place]; πέτρᾳ should be read in [Refs 5th c.BC+]; the distinction is minimized by [Refs 2nd c.AD+]
II. proverbial, οὐκ ἀπὸ δρυὸς οὐδ᾽ ἀπὸ πέτρης, etc. (see. δρῦς); as a symbol of firmness, ὁ δ᾽ ἐστάθη ἠΰτε π. ἔμπεδον [Refs 8th c.BC+]; of hard-heartedness, ἐκ πέτρας εἰργασμένος [Refs 5th c.BC+] in a text with musical accompaniment, [Refs]