Quick Definition
μαρτύρομαι v. I call to witness, testify, solemnly charge
Strong's Definition
middle voice from 3144; to be adduced as a witness, i.e. (figuratively) to obtest (in affirmation or exhortation)
KJV Usage: take to record, testify
UBS Dictionary of the Greek New Testament
verb | μαρτυρέω
33.223 · Communication · Assert, Declare
to declare, to assert, to testify to make a serious declaration on the basis of presumed personal knowledge
1 It is possible that διαμαρτύρομαι[a] is somewhat stronger and more emphatic than μαρτύρομαι[a], but this cannot be shown from NT contexts. 2 It is possible that διαμαρτύρομαι[b] is somewhat more emphatic in connotation than μαρτύρομαι[b], but this cannot be determined from existing contexts.
UBS Dictionary of the Greek New Testament © United Bible Societies, licensed CC BY-SA 4.0.
Thayer's Greek Lexicon
μαρτύρομαι (fr. μάρτυρ [cf. μάρτυς); 1. tocitea witness, bring forward a witness, call to witness, (Tragg., Thuce., Plato, sqq.); to affirm by appeal to God, to declare solemnly, protest: ταῦτα, Plat. Phil. p. 47 ¢.; ὅτι, Acts xx. 26; Gal. v. 3. 2. to conjure, beseech as in God's name, exhort solemnly: τινί, Acts xxvi. 22 L T Tr WH; foll. by the ace. ν΄. inf., Eph. iv. 17; εἰς τό foll. by ace. w. inf. [ef. B. § 140, 10, 3], 1 Th. ii. 12 (11) T Tr WH. [Compe.: δια-, προ-μαρτύρομαι.]
Mounce Concise Greek Dictionary
μαρτύρομαι martyromai 5x
to call to witness; intrans. to make a solemn affirmation or declaration, Acts 20:26; 26:22; Gal. 5:3; to make a solemn appeal, Eph. 4:17; 1 Thess. 2:12*
Abbott-Smith Greek Lexicon
** μαρτύρομαι
(< μάρτυρ), [in LXX: Jth 7:28, I Mac 2:56 א)*;]
to summon as witness (M, Th., 25 f.; Hort., 1Pe., 53 f.; Lft., Notes, 29; Ga 203), hence, to protest, affirm solemnly: seq. ὅτι, Ac 20:26, Ga 5:3;
to adjure, beseech: c. dat. pers., Ac 26:22; c. acc. et inf., Eph 4:17; seq. εἰς, I Th 2:12 (cf. δια-, προ-μαρτύρομαι).†
Moulton & Milligan — Vocabulary of the Greek NT
μαρτύρομαι. For this verb in its original sense of ‘‘summon to witness’’ cf. P Oxy VIII. 11148 (A.D. 237) ἐμαρτύρατο τοὺς τόδε TO μαρτυροποίημα σφραγίζειν μέλλοντας, ‘called to witness the persons about to seal the present affidavit” (Ed.). From this it is an easy transition to the meaning “asseverate,” as in 26. IIT. 4715: (1i/A.D.) μαρτύρονται κύριε τὴν σὴν τύχην, ‘“‘they swear by your Fortune, my lord,” and in Mahaffy’s restoration of P Petr II. 46 (a)? (B.C. 200) μαρτύρομαι βασιλέα ἸΤτολεμαῖον. This again passes into ‘‘solemnly charge,” the translation which Hort (ad 1 Pet 111) prefers in 1 Thess 215, Eph 417. According to Lightfoot (ad 1 Thess 215 ; cf. note on Gal 55) μαρτύρομαι is never ‘‘bear witness to” in the NT any more than in class. Greek, but exx. of this usage can be quoted from the Kouwn, e.g. P Oxy VIII. 11201 (early iii/A.p.) κατὰ τοῦτο μαρτύρομαι τὴν βίαν γυνὴ χήρα Kal ἀσθενής, “1 accordingly testify to his violence, being a feeble widow woman”’ (Ed.), P Amh II. 1414? (A.p. 350) ἐπιδίδωμι τῇ ἐπιεικείᾳ [σο]υ τάδε τὰ βιβλία [poly τοσοῦτο μαρτυραμένη, “1 present this my petition to your excellency, bearing witness to the facts” (Edd.), P Strass I. 513. (iii/A.p.) βιβλία ἐπιδεδώκαμεν τῷ [σ]τρατηγῷ αὐτὰ ταῦτα μαρτυρόμενοι, and similarly P Thead 2116 (a.p. 318).
Liddell-Scott-Jones — Greek-English Lexicon
μαρτύρομαι (marturomai) — to testify. μαρτύρομαι [ῡ], future μαρτῠροῦμαι (δια-) [LXX+2nd c.AD+]: aorist ἐμαρτῡράμην [Refs 5th c.BC+]:—call to witness, invoke, with accusative person, [Refs 5th c.BC+]; especially of the gods, Ἄρτεμιν, γαῖαν καὶ θεούς, [Refs 5th c.BC+]; δαίμονας, ὡς.. [Refs]: with accusative et infinitive, ὑμᾶς δ᾽ ἀκούειν ταῦτ᾽ ἐγὼ μαρτύρομαι [Refs 4th c.BC+]participle, μαρτύρομαι τυπτόμενος I call you to witness that.., [Refs 5th c.BC+]
2. with accusative of things, call one to witness a thing, [Refs 5th c.BC+]
3. protest, asseverate, μ. ὅτι.. [Refs 5th c.BC+] I protest, [Refs 5th c.BC+]
4. with accusative person et genitive of things, οἱ δὲ τῆς τῶν θεῶν.. παραγωγῆς τὸν Ὅμηρον μ. ὅτι.. cite Homer as a witness of.., [Refs 5th c.BC+] [same place]; μ. τινὶ ὅτι.. [NT]; τοὺς ἀποστάντας μ. τῆς ἐπιορκίας remind them of.., [Refs 2nd c.AD+]