Quick Definition
I knock
Strong's Definition
to rap
Derivation: apparently a primary verb;
KJV Usage: knock
Thayer's Greek Lexicon
κρούω; 1 aorist participle κρουσας; to knock: τήν θύραν, to knock at the door, Luk_13:25; Act_12:13 (Aristophanes eccles. 317, 990; Xenophon, symp. 1, 11; Plato, Prot., p. 310 a.; 314 d.; symp. 212 c.; but κόπτειν τήν θύραν is better, according to Phryn. with whom Lobeck agrees, p. 177 (cf. Schmidt (chapter 113, 9), who makes κόπτειν to knock with a heavy blow, κρούειν to knock with the knuckles)); without τήν θύραν (cf. Winer's Grammar, 593 (552)), Mat_7:7; Luk_11:9-10; Luk_12:36; Act_12:16; Rev_3:20 (on which see θύρα, c. ἐ.).
Mounce Concise Greek Dictionary
κρούω krouō 9x
to knock at a door, Mat_7:7-8 ; Luk_11:9-10 ; Luk_12:36 ; Luk_13:25 ; Act_12:13 ; Act_12:16 ; Rev_3:20
Abbott-Smith Greek Lexicon
Κρούω ,
[in LXX : seq . ἐπί Jdg_19:22 , Son_5:2 ( H1849 );]
c , acc , τ . αὐλαίαν , Jdt_14:14 * ;]
to strike, knock: at a door (Κόπτειν , in Att. .), Mat_7:7-8 , Luk_11:9-10 ; Luk_12:36 , Act_12:16 , Rev_3:20 ; c . acc , τ . θύραν , Luk_13:25 , Act_12:13 .†
Moulton & Milligan — Vocabulary of the Greek NT
κρούω [page 361]
For this verb of knocking at the door, as in Luk_13:25 , Act_12:13 , where the Purists would have preferred κόπτω (cf. Lob. Phryn. p. 177 f.). see P Par 50 .7 (B.C. 160) εἶδον Πτολεμαῖον . . . κρού [οντα ] θύραν . Other exx. of this usage in late Greek are given in Field Notes , p. 120. In the magic P Lond 46 .75 (iv/A.D.) (= I. p. 67) we have κροῦε εἰς τὸ οὖς́ λέγων κτλ . For the subst. κροῦμα see BGU IV. 1125 .4, .31 (B.C. 13), and for the compd. ἐκκρούω in the sense of put off, evade, cf. P Fay 109 .9 (early i/A.D.) Σέλευκος γάρ μου αὐτοὺς ὧδε ἐκκ [έκ ]ρουκε λέγων ὅτι συνέστακας ἑαυτῶι , Seleucus has evaded paying the money by saying that you have made an arrangement with him (to pay instead) (Edd.).
Liddell-Scott — Intermediate Greek Lexicon
κρούω "to strike, smite: to strike" one "against" another, κρ. χεῖρας "to clap" hands, Eur. ; κρ. τὰ ὅπλα πρὸς ἄλληλα Thuc. , etc.:— κρ. τὸν πόδα (i. e. κρ. τὴν γῆν τῶι ποδί) in dancing, Eur. κέραμον κρούειν "to tap" an earthen vessel, to try whether it rings sound: hence "to examine, prove", Plat. "to strike" a lyre with the plectron, id=Plat. κρούειν τὴν θύραν "to knock at" the door "on the outside", Xen. , etc. as a nautical term, in Mid., κρούεσθαι πρύμναν, like ἀνακρούεσθαι, "to back" a ship, Thuc.
STEPBible — Tyndale Abridged Greek Lexicon
Κρούω
[in LXX: before ἐπί Jdg.19:22, Sng.5:2 (דָּפַק) ;]
with, accusative, τ. αὐλαίαν, Jdth.14:14 * ;]
to strike, knock: at a door (Κόπτειν, in Att..), Mat.7:7-8, Luk.11:9-10 12:36, Act.12:16, Rev.3:20; with accusative, τ. θύραν, Luk.13:25, Act.12:13.†
(AS)