Lexical Definition

‎συστροφή‎ systrophḗ (soos-trof-ay') commotion/plot ^G:N-F
from ‎συστρέφω‎

+ band together, concourse.

• a twisting together, i.e. (figuratively) a secret coalition, riotous crowd

Abbott-Smith

συ-στροφή, -ῆς, ἡ (< συστρέφω), [in LXX: Ho 4:19 13:12 (צרר); σ. ποιεῖσθαι, Am 7:10 (קשׁר), etc. ;]
1. a twisting together (Plat.).
2. a concourse, a riotous gathering (Polyb.): Ac 19:40; σ. ποιεῖσθαι (Am, l.c.), to make a compact (RV, banded themselves together): Ac 23:12.†

Abbott-Smith References

Liddell-Scott-Jones

συστροφή-ή, ἡ,

twisting together, σ. χαύνην λαμβάνειν to be loosely twisted, of yarn, [Refs 5th c.BC+]

__2 turning round, variant (cited in [Refs 1st c.AD+]
__3 condensation, density, [Refs 4th c.BC+]
__4 plural, dealings, converse between men, [Refs 4th c.BC+]
__5 metaphorically of style, terseness, concentration, [συστροφήῇ ">Refs 4th c.BC+]concisely, [Refs]
__II that which is rolled into one mass: hence,
__II.1 collection, gathering, πλήθεος σ. [Refs 5th c.BC+]; seditious meeting, concourse, [NT+2nd c.BC+]; κατὰ συστροφήάς in knots, [Refs 1st c.BC+]; μετὰ συστροφήῆς in close array, [Refs 1st c.BC+]; also, swarm of bees, [LXX]; flock of birds, [Refs 2nd c.AD+]; of other things, σ. δρυῶν [Refs 1st c.AD+]
__II.2 physical mass, aggregate, in plural, [Refs 4th c.BC+]; especially morbid collection or deposit of tubercles, [Refs 5th c.BC+]; αἱ περὶ τοὺς κονδύλους σ. chalk-stones, [Refs 1st c.AD+]; σ. νεύρων a complication of nerves or sinews, [συστροφήαὶ νοσημάτων 5th c.BC: Hippocrates Medicus “Acut.(Sp.”) 4">Refs 5th c.BC+]; tumour, [Refs 5th c.BC+]
__II.3 twisted grain in wood, [Refs 4th c.BC+]
__II.4 συστροφήή, with or without ὄμβρου, a sudden storm of rain, [Refs 2nd c.BC+]; σ. ἀνέμου, πνεύματος, whirlwind, [LXX+4th c.BC+]; νέφη καὶ σ. [Refs 3rd c.BC+]
__II.5 of stars, νεφελοειδὴς σ., = nebula, [Refs 2nd c.AD+]

_{LSJ Scripture Refs: Acts.19.40 ☩ LXX.Judg.14.8 ☩ LXX.Hos.4.19}