Lexical Definition

‎συντίθεμαι‎ syntíthemai (soon-tith'-em-ahee) to agree ^G:V
middle voice from ‎σύν‎ and ‎τίθημι‎

agree, assent, covenant.

• to place jointly, i.e. (figuratively) to consent (bargain, stipulate), concur

Abbott-Smith

συν-τίθημι [in LXX: I Ki 22:13 (קשׁר), etc. ;]
to place or put together, in various senses. Mid.,
(a) to observe, perceive;
(b) to determine, agree, covenant: c. inf., Lk 22:5; seq. τοῦ, c. inf., Ac 23:20; seq. ἵνα, Jo 9:22.†

Abbott-Smith References

Liddell-Scott-Jones

συντίθημι,

used by [Refs 8th c.BC+]middle, see below:—passive (see. below), but σύγκειμαι is more frequently as passive:— place or put together, τὴν οὐρὴν καὶ τὸν σπλῆνα.. συνθεὶς ὁμοῦ [Refs 5th c.BC+]; σ. ἱμάτια, opposed to ἀνασείειν, fold them together, [Refs 5th c.BC+]; σ. σκέλη, opposed to ἐκτείνειν, [Refs]; opposed to διαιρεῖσθαι, [Refs 5th c.BC+]; σ. ἄρθρα στόματος close the lips, [Refs 5th c.BC+]; εἰς τὸ οὖλον (αυλον codex) σ. τὴν κόμην, = calamistrat, [Refs] —passive, τὸ συντίθεσθαι καθ᾽ ὁντινοῦν τρόπον ῥῖγος οὐκ ἀγαθόν ἐστι any sort of combination of shivering (with other symptoms), [Refs 2nd c.AD+]

__2 technical uses,
__2.a in Mathematics texts, add together, of numbers, [Refs 5th c.BC+]; τό τε ἀρχαῖον καὶ τὸ ἔργον principal and interest, [Refs 4th c.BC+]: Geometry texts, of lines and figures, [Refs 3rd c.BC+]
__2.b in Mathematics texts also, of the transformation of a ratio componendo, [Refs 4th c.BC+]
__2.c Logic, combine the terms of a proposition, [Refs 4th c.BC+]; also, use the fallacy of composition [Refs]
__2.d Rhet., accumulate, joined with ἐποικοδομεῖν (to form a climax), [Refs]
__2.e σ. λόγον make up an account, [Refs 3rd c.BC+]
__II put together constructively, so as to make a whole, πεντηκοντέρους καὶ τριήρεας (as a bridge) [Refs 5th c.BC+]; λίθους, of builders, [Refs 5th c.BC+]; πλίνθους, ξύλα, [Refs 5th c.BC+]; τὰ κομισθέντα [Refs 5th c.BC+]
__II.2 construct, frame, τὸ θνητὸν γένος [Refs 5th c.BC+]; ὁ συνθείς the creator, [Refs]:—passive, to be constructed, of the material universe, opposed to διαλύεσθαι, [Refs 4th c.BC+]
__II.2.b σ. τι ἀπό τινος compose or make one thing of or from another, [Refs 5th c.BC+]; εἴδωλον οὐρανοῦ ξυνθεῖσ᾽ ἄπο (Reiske for ὕπο) [Refs 5th c.BC+]; δυοῖν ἅμιλλαν ξ. strive for two things at once, [Refs 5th c.BC+]
__II.3 construct or frame a story, συνθέντες λόγον [Refs 5th c.BC+]; narrate in writing, τὰ Ἑλληνικά [Refs 5th c.BC+]; compose, σ. μύθους, ποίησιν, μελῳδίαν, ὄρχησιν, [Refs 5th c.BC+] —passive, perfect συντέθειται[Refs]; περὶ ὀλίγας οἰκίας αἱ.. τραγῳδίαι συντίθενται [Refs 4th c.BC+]
__II.4 in Mathematics texts, of the synthesis of a geometrical problem, opposed to ἀναλύω, [Refs 3rd c.AD+]; συντεθήσεται τὸ πρόβλημα οὕτως the synthesis of the problem will proceed thus, [Refs 3rd c.BC+]
__II.5 frame, devise, contrive, ὁ συνθεὶς τάδε the framer of this plot, [Refs 5th c.BC+]; rarely in good sense, εὖ πρᾶγμα συντεθὲν ὄψεσθε [Refs 4th c.BC+]
__II.6 put together, take in, comprehend, παιδὸς μόρον [Refs 5th c.BC+] putting things shortly together, speaking briefly, [Refs 5th c.BC+]
__III commit to a person's care, deliver to him for his own use or that of others, [Refs 3rd c.BC+]; γνώριζε οὐχ ὑπάρχον παρ᾽ ἡμῖν ἀργύριον τοσοῦτο ὥστε ἱκανὸν συνθεῖναι Πυρρίχῳ [Refs 3rd c.BC+]; τινὶ ὀστᾶ, ἐπιστολάς, πλῆθος χρυσίου, etc., [Refs 2nd c.BC+]
__III.2 αὐτοὶ δ᾽ ἔνοχοι εἴημεν τῷ ὅρκῳ ὁπηνίκ᾽ ἂν εὖ συνθῶμεν perhaps as soon as we have duly delivered (or executed) this declaration, [Refs 1st c.BC+]; συνθεὶς τούτους μου τοὺς λιβέλλους ἐπιδίδωμι τῇ σῇ λαμπρότητι [Refs 6th c.AD+]
__IV collect, conclude, infer, [Refs 2nd c.BC+]
__B middle συντίθεμαι, used by [Refs 8th c.BC+]aorist 2 and in signification [Refs]
__B.I put together for oneself, i.e. observe, give heed to, σύνθετο θυμῷ βουλήν [Refs 8th c.BC+]; and, simply, perceive, hear, κλαιούσης ὄπα σύνθετο [Refs 8th c.BC+] do thou take heed, [Refs 8th c.BC+]
__B.I.2 set in order organize, δύναμιν [Refs 5th c.BC+]
__B.II agree on, conclude (compare συνθήκη), ἄνδρεσσι κακοῖς συνθέμενοι φιλίην [Refs 6th c.BC+]; συντίθεσθαι συμμαχίην, ὁμαιχμίην τισί, [Refs 5th c.BC+].á; τὰς ξυνθήκας ἂς ξυνέθεντο [Refs 5th c.BC+]; σ. ναῦλον agree upon the fare, [Refs 5th c.BC+]; ταῦτα συνθέμενοι having agreed on these points, [Refs 5th c.BC+]with [Refs 5th c.BC+] —passive, τοῦ συντεθέντος χρόνου agreed upon, [Refs 5th c.BC+]
__B.II.2 with infinitive, covenant, agree to do, συνέθευ παρέχειν φωνάν [Refs 5th c.BC+]: with infinitive future, ξυνέθεντο ἥξειν [Refs 5th c.BC+]; σ. τινί followed by infinitive future, συνθέμενοι ἡμῖν.. ἀντιώσεσθαι [Refs 5th c.BC+]infinitive must be supplied in the phrases, κατὰ (i.e. καθ᾽ ἃ) συνεθήκαντο, καθ᾽ ὅτι ἂν συνθῶνται, etc., [Refs 5th c.BC+]
__B.II.3 absolutely, make a covenant, ἔβαν συνθέμενος [Refs 7th c.BC+]; αὐτὸς σαυτῷ συνέθου [Refs 5th c.BC+]; συνθέσθαι πρός τινα come to terms with him, Decrees cited in [Refs 4th c.BC+]; περί τινος πρὸς ἀλλήλους [Refs 1st c.BC+]; also, bet, wager, [Refs 4th c.BC+]
__B.II.4 vote with, support, τούτοις [Refs 5th c.BC+]; assent to, πᾶσι τοῖς προκειμένοις [Refs 2nd c.AD+]; ἵνα μὴ δόξω συνθέσθαι τῇ τοῦ πραγματικοῦ ἀγνοίᾳ [Refs 3rd c.AD+]
__B.II.5 conclude, infer [Refs 4th c.BC+] —passive, τὰ ὕστερον -τεθησόμενα[Refs]