LSJ Gloss:συνδρομήa tumultuous concourseDodson:συνδρομήa running togethera running together, concourse, mob.
Strong's:συνδρομή a running together, i.e. (riotous) concourseDerivation: from (the alternate of) G4936;KJV Usage: run together. G4936
TBESG:συνδρομήswarmingG:N-F συνδρομή, -ῆς, ἡ (< συντρέχω), [in LXX: Refs Jdth.10:18, 3Ma.3:8 * ;] concourse, esp. of a riotous gathering: Act.21:30 (Arist., Polyb., al.).† (AS)
συνδρομή sundromē soon-drom-ay' From (the alternate of) G4936; a running together, that is, (riotous) concourseKJV Usage: run together.
συντρέχω suntrechō soon-trekh'-o From G4862 and G5143 (including its alternate); to rush together (hastily assemble) or headlong (figuratively)KJV Usage: run (together, with).
ἐπισυντρέχω episuntrechō ep-ee-soon-trekh'-o From G1909 and G4936; to hasten together upon one place (or a particular occasion)KJV Usage: come running together.