Quick Definition
I unite in bearing witness
Strong's Definition
to testify further jointly, i.e. unite in adding evidence
Derivation: from G4862 (σύν) and G1957 (ἐπιμαρτυρέω);
KJV Usage: also bear witness
Thayer's Greek Lexicon
συνεπιμαρτυρέω, συνεπιμαρτύρω, participle genitive singular masculine συνεπιμαρτυροῦντος; to attest together with; to join in bearing witness, to unite in adding testimony: Heb_2:4. (Aristotle, Polybius, (Plutarch), Athen., Sextus Empiricus; Clement of Rome, 1 Cor. 23, 5 [ET]; 43, 1 [ET].)
STRONGS NT 4901a: συνεπιτίθημισυνεπιτίθημι: 2 aorist middle συνεπεθεμην; to place upon (or near) together with, help in putting on; middle to attack jointly, to assail together, set upon with (see ἐπιτίθημι, 2 b.): Act_24:9 G L T Tr WH (R. V. joined in the charge) (so in Thucydides 6, 10; Xenophon, Cyril 4, 2, 3; Plato, Phileb., p. 16 a.; Polybius 5, 78, 4; Diodorus 1, 21).
Mounce Concise Greek Dictionary
συνεπιμαρτυρέω synepimartyreō 1x
to join in according testimony; to support by testimony, to confirm, sanction, Heb_2:4
συνεπιτίθημι synepitithēmi 1x
can also be spelled συνεπιτίθεμαι , mid., to set upon along with, join with others in an attack; to unite in impeaching, Act_24:9
Abbott-Smith Greek Lexicon
* συν -επι -μαρτυρέω , -ῶ ,
to join in attesting, bear witness together with: Heb_2:4 ( Arist ., Polyb ., a1.).†
Moulton & Milligan — Vocabulary of the Greek NT
συνεπιμαρτυρέω [page 605]
bear witness together with ( Heb_2:4 ) : cf. Aristeas 191 συνεπιμαρτυρήσας δὲ τούτῳ τὸν ἐχόμενον ἠρώτα , he expressed his approval and asked the next (Thackeray).
STEPBible — Tyndale Abridged Greek Lexicon
συν-επι-μαρτυρέω, -ῶ
to join in attesting, bear witness together with: Heb.2:4 (Arist., Polyb., a1.).†
(AS)