Quick Definition
σύνειμι v. I am with
Strong's Definition
to be in company with, i.e. present at the time
Derivation: from G4862 (σύν) and G1510 (εἰμί) (including its various inflections);
KJV Usage: be with
Thayer's Greek Lexicon
σύν-ειμι, ptep. gen. plur. masc. συνόντων : impf. 3 pers. plur. συνῆσαν; (σύν, and εἰμί to be) ; fr. Hom. Od. 7, 270 down; to be with: τινί, one, Lk. ix. 18 [WH mrg. συνήντηcay]; Acts xxii. 11.
Mounce Concise Greek Dictionary
Abbott-Smith Greek Lexicon
σύν-ειμι
(< εἰμί to be), [in LXX: Je 3:20 (רֵעַ), al. ;]
to be with: Lk 9:18 (WH, mg., συνήντησαν), Ac 22:11.†
Moulton & Milligan — Vocabulary of the Greek NT
σύνειμι (from εἶμι, ““σο᾽᾽), ‘come together,” is found in the NT only in Lk 84. All Preisigke’s exx. from the papyri are late, e.g. P Lond V. 1674%® (c. a.D. 570) and 7. 168631 (A.D. 565).
Liddell-Scott-Jones — Greek-English Lexicon
σύνειμι (suneimi) — be with. σύνειμι, (εἶμι ibo) go or come together, assemble, ἐς χῶρον ἕνα ξυνιόντες ἵκοντο [Refs 8th c.BC+]; συνιόντος ὄχλου πολλοῦ [NT]
2. in hostile sense, meet in battle, [Refs 8th c.BC+]; of states, engage in war, [Refs 5th c.BC+]
3. in peaceable sense, come together, meet to consult or deliberate,[Refs 4th c.BC+]; of a conspirator, σ. τοῖς φυγάσιν ἐπὶ καταλύσει τοῦ δήμου [Refs 4th c.BC+]; also of festive meetings, συνόδους συνιέναι [Refs 5th c.BC+]
3. b of the council, σύλλογον ὃν εἶπες συνιέναι [Refs]
4. σ. εἰς τὴν κοινωνίαν, of marriage, [Refs]; of copulation of animals, [Refs 4th c.BC+]
II. of things, gather, σ. ἀήρ [Refs 5th c.BC+]; of clouds, [Refs 4th c.BC+]; opposed to χωρίζεσθαι, [Refs]; σ. πρὸς αὑτήν recur, [Refs 5th c.BC+]
II.2. of money, come together, come in, of revenue, [Refs 5th c.BC+]
II.3. to be contracted, σ. καὶ ψύχεσθαι [Refs 4th c.BC+]
II.4. of stars, come into conjunction, [Refs 4th c.AD+]; of the moon, συνιούσης, opposed to αὐξομένης, [Refs 6th c.AD+]