From sun and echo; to hold together, i.e. To compress (the ears, with a crowd or siege) or arrest (a prisoner); figuratively, to compel, perplex, afflict, preoccupy -- constrain, hold, keep in, press, lie sick of, stop, be in a strait, straiten, be taken with, throng.
see GREEK sun
see GREEK echo
1. to hold together; any whole, lest it fall to pieces or something fall away from it: τό συνέχον τά πάντα, the deity as holding all things together, Wis. 1:7 (see Grimm at the passage).
2. to hold together with constraint, to compress, i. e., a. to press together with the hand: τά ὦτα, to stop the ears, Acts 7:57 (τό στόμα, Isaiah 52:15; τόν οὐρανόν, to shut, that it may not rain, Deuteronomy 11:17; 1 Kings 8:35).
3. to hold completely, i. e.
a. to hold fast : properly, a prisoner, Luke 22:63 (τά αἰχμάλωτα, Lucian, Tox. 39); metaphorically, in the passive, to be held by, closely occupied with, any business (Wis. 17:19 (20); Herodian, 1, 17, 22 (9 edition, Bekker); Aelian v. h. 14, 22): τῷ λόγῳ, in teaching the word, Acts 18:5 G L T Tr WH (here R. V. constrained by). β. to constrain, oppress, of ills laying hold of one and distressing him; passive, to be holden with equivalent to afflicted with, suffering from": νόσοις, Matthew 4:24; πυρετῷ, Luke 4:38; δυσεντερίῳ, Acts 28:8 (many examples from Greek writings from Aeschylus and Herodotus down are given in Passow, under the word συνέχω, I. a.; (Liddell and Scott, under the word, I. 4)); of affections of the mind: φόβῳ, Luke 8:37 (ὀδύρμω, Aelian v. h. 14, 22; ἀλγηδονι, Plutarch, de fluv. 2, 1; ἀθυμία, ibid. 7, 5; 19, 1; λύπη, 17, 3; for other examples see Grimm on Wis. 17:10). γ. to urge, impel: tropically, the soul, ἡ ἀγάπη ... συνέχει ἡμᾶς, 2 Corinthians 5:14 (A. V. constraineth); πῶς (how greatly, how sorely) συνέχομαι, Luke 12:50 (A. V. straitened); τῷ πνεύματι, Acts 18:5 Rec. συνέχομαι ἐκ τῶν δύο, I am hard pressed on both sides, my mind is impelled or disturbed from each side (R. V. I am in a strait betwixt the two), Philippians 1:23.