The Collaborative International Dictionary of English v.0.48:

Swarm \Swarm\, v. i. [imp. & p. p. Swarmed; p. pr. & vb. n.
   Swarming.]
   1. To collect, and depart from a hive by flight in a body; --
      said of bees; as, bees swarm in warm, clear days in
      summer.
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   2. To appear or collect in a crowd; to throng together; to
      congregate in a multitude. --Chaucer.
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   3. To be crowded; to be thronged with a multitude of beings
      in motion.
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            Every place swarms with soldiers.     --Spenser.
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   4. To abound; to be filled (with). --Atterbury.
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   5. To breed multitudes.
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            Not so thick swarmed once the soil
            Bedropped with blood of Gorgon.       --Milton.
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The Collaborative International Dictionary of English v.0.48:

Swarm \Swarm\, v. i. [Cf. Swerve.]
   To climb a tree, pole, or the like, by embracing it with the
   arms and legs alternately. See Shin. [Colloq.]
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         At the top was placed a piece of money, as a prize for
         those who could swarm up and seize it.   --W. Coxe.
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The Collaborative International Dictionary of English v.0.48:

Swarm \Swarm\, n. [OE. swarm, AS. swearm; akin to D. zwerm, G.
   schwarm, OHG. swaram, Icel. svarmr a tumult, Sw. sv[aum]rm a
   swarm, Dan. svaerm, and G. schwirren to whiz, to buzz, Skr.
   svar to sound, and perhaps to E. swear. [root]177. Cf.
   Swerve, Swirl.]
   1. A large number or mass of small animals or insects,
      especially when in motion. "A deadly swarm of hornets."
      --Milton.
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   2. Especially, a great number of honeybees which emigrate
      from a hive at once, and seek new lodgings under the
      direction of a queen; a like body of bees settled
      permanently in a hive. "A swarm of bees." --Chaucer.
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   3. Hence, any great number or multitude, as of people in
      motion, or sometimes of inanimate objects; as, a swarm of
      meteorites.
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            Those prodigious swarms that had settled themselves
            in every part of it [Italy].          --Addison.
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   Syn: Multitude; crowd; throng.
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The Collaborative International Dictionary of English v.0.48:

Swarm \Swarm\, v. t.
   To crowd or throng. --Fanshawe.
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WordNet (r) 3.0 (2006):

swarm
    n 1: a moving crowd [syn: drove, horde, swarm]
    2: a group of many things in the air or on the ground; "a swarm
       of insects obscured the light"; "clouds of blossoms"; "it
       discharged a cloud of spores" [syn: swarm, cloud]
    v 1: be teeming, be abuzz; "The garden was swarming with bees";
         "The plaza is teeming with undercover policemen"; "her mind
         pullulated with worries" [syn: teem, pullulate,
         swarm]
    2: move in large numbers; "people were pouring out of the
       theater"; "beggars pullulated in the plaza" [syn: pour,
       swarm, stream, teem, pullulate]

Moby Thesaurus II by Grady Ward, 1.0:

145 Moby Thesaurus words for "swarm":
   a mass of, a world of, abound, abound with, army, assemble, beset,
   bevy, bristle with, bunch, bunch up, burst with, charm, clot,
   cloud, cluster, clutter, collect, come together, congregate,
   converge, copulate, couple, covey, crawl, crawl with, creep with,
   crowd, date, drove, emigrate, emigration, expatriate, expatriation,
   fill, flight, flit, flock, flock together, flocks, flood, flow,
   flow together, forgather, fuse, gaggle, gang around, gang up,
   gather, gather around, hail, herd, herd together, hive, horde,
   host, huddle, immigrate, immigration, in-migrate, in-migration,
   infest, infestation, intermigrate, intermigration, invade,
   invasion, jam, know no bounds, large amount, league, legion, link,
   lots, lousiness, luxuriate, many, mass, masses of, meet, merge,
   migrate, migration, mill, mob, muchness, multitude, murmuration,
   muster, nest, numbers, out-migrate, out-migration, overabound,
   overbrim, overflow, overgrow, overrun, overrunning, overspill,
   overspread, overspreading, overswarm, overswarming, pack, passage,
   plague, plurality, pullulate, quantities, quite a few, rally,
   rally around, ravage, remigrate, remigration, rendezvous, rout,
   ruck, run, run riot, scores, seethe, shoal, skein, spill over,
   spring, stream, superabound, surge, swarm with, swarming,
   take wing, teem, teem with, teeming, throng, throng with, tidy sum,
   transmigrate, transmigration, trek, unite, watch, worlds of