thun·der·clap /-ˌklæp/
  雷聲,霹靂
  Thun·der·clap n. A sharp burst of thunder; a sudden report of a discharge of atmospheric electricity. “Thunderclaps that make them quake.”
     When suddenly the thunderclap was heard.   --Dryden.
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  thunderclap
       n 1: a single sharp crash of thunder
       2: a shocking surprise; "news of the attack came like a
          bombshell" [syn: bombshell, thunderbolt]