Swarm | Define Swarm at Dictionary.com
"cloud of bees or other insects," O.E. swearm, from P.Gmc. *swarmaz (cf. O.S., M.L.G. swarm, Swed. svärm, M.Du. swerm, O.H.G. swarm, Ger. Schwarm "swarm;" O.N. svarmr ... sound. But OED suggests possible connection with base of swerve and ground ...