The Collaborative International Dictionary of English v.0.48:

Thunder \Thun"der\, n. [OE. [thorn]under, [thorn]onder,
   [thorn]oner, AS. [thorn]unor; akin to [thorn]unian to
   stretch, to thunder, D. donder thunder, G. donner, OHG.
   donar, Icel. [thorn][=o]rr Thor, L. tonare to thunder,
   tonitrus thunder, Gr. to`nos a stretching, straining, Skr.
   tan to stretch. [root]52. See Thin, and cf. Astonish,
   Detonate, Intone, Thursday, Tone.]
   1. The sound which follows a flash of lightning; the report
      of a discharge of atmospheric electricity.
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   2. The discharge of electricity; a thunderbolt. [Obs.]
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            The revenging gods
            'Gainst parricides did all their thunders bend.
                                                  --Shak.
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   3. Any loud noise; as, the thunder of cannon.
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   4. An alarming or statrling threat or denunciation.
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            The thunders of the Vatican could no longer strike
            into the heart of princes.            --Prescott.
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   Thunder pumper. (Zool.)
      (a) The croaker (Haploidontus grunniens).
      (b) The American bittern or stake-driver.

   Thunder rod, a lightning rod. [R.]

   Thunder snake. (Zool.)
      (a) The chicken, or milk, snake.
      (b) A small reddish ground snake (Carphophis amoena syn.
          Celuta amoena) native to the Eastern United States;
          -- called also worm snake.

   Thunder tube, a fulgurite. See Fulgurite.
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The Collaborative International Dictionary of English v.0.48:

Thunder \Thun"der\, v. t.
   To emit with noise and terror; to utter vehemently; to
   publish, as a threat or denunciation.
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         Oracles severe
         Were daily thundered in our general's ear. --Dryden.
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         An archdeacon, as being a prelate, may thunder out an
         ecclesiastical censure.                  --Ayliffe.
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The Collaborative International Dictionary of English v.0.48:

Thunder \Thun"der\, v. i. [imp. & p. p. Thundered; p. pr. &
   vb. n. Thundering.] [AS. [thorn]unrian. See Thunder, n.]
   1. To produce thunder; to sound, rattle, or roar, as a
      discharge of atmospheric electricity; -- often used
      impersonally; as, it thundered continuously.
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            Canst thou thunder with a voice like him? --Job xl.
                                                  9.
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   2. Fig.: To make a loud noise; esp. a heavy sound, of some
      continuance.
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            His dreadful voice no more
            Would thunder in my ears.             --Milton.
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   3. To utter violent denunciation.
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WordNet (r) 3.0 (2006):

thunder
    n 1: a deep prolonged loud noise [syn: boom, roar,
         roaring, thunder]
    2: a booming or crashing noise caused by air expanding along the
       path of a bolt of lightning
    3: street names for heroin [syn: big H, hell dust, nose
       drops, smack, thunder, skag, scag]
    v 1: move fast, noisily, and heavily; "The bus thundered down
         the road"
    2: utter words loudly and forcefully; "`Get out of here,' he
       roared" [syn: thunder, roar]
    3: be the case that thunder is being heard; "Whenever it
       thunders, my dog crawls under the bed" [syn: thunder,
       boom]
    4: to make or produce a loud noise; "The river thundered below";
       "The engine roared as the driver pushed the car to full
       throttle"