Lexical Definition

‎συνδρομή‎ syndromḗ (soon-drom-ay') swarming ^G:N-F
from (the alternate of) ‎συντρέχω‎

run together.

• a running together, i.e. (riotous) concourse

Abbott-Smith

** συνδρομή, -ῆς, ἡ (< συντρέχω), [in LXX: Jth 10:18, III Mac 3:8 * ;]
a concourse, esp. of a riotous gathering: Ac 21:30 (Arist., Polyb., al.).†

Abbott-Smith References

Liddell-Scott-Jones

συνδρομή-ή, ἡ,

tumultuous concourse of people, [NT+5th c.BC+]; ἐπί τινα, κατά τινων, [Refs 2nd c.BC+]; ἀπὸ συνδρομήῆς tumultuously, [Refs 1st c.BC+]

__2 of things, στενὴ πορθμοῦ σ. (compare {συνδρομήάς}) [Refs 3rd c.BC+]; σ. αἵματος εἰς τὸν πληγέντα τόπον a determination of blood, [Refs 4th c.BC+]; combination, κέκληται ἡ σ. τούτων καυλός [Refs 1st c.BC+]; ἡς. τοῦ λόγου its conclusion, moral, [Refs 5th c.AD+]; especially in Medicine texts, concurrence of symptoms, 'clinical picture', [Refs 2nd c.AD+]
__2.b contraction of a muscle, [Refs 2nd c.AD+]; of the prepuce, [Refs 7th c.AD+]
__3 in Rhet., provisional concession of an adversary's standpoint, [Refs 2nd c.AD+]

_{LSJ Scripture Refs: Acts.21.30}