The Collaborative International Dictionary of English v.0.48:

Fulminate \Ful"mi*nate\, v. i. [imp. & p. p. Fulminated; p.
   pr. & vb. n. Fulminating.] [L. fulminatus, p. p. of
   fulminare to lighten, strike with lightning, fr. fulmen
   thunderbolt, fr. fulgere to shine. See Fulgent, and cf.
   Fulmine.]
   1. To thunder; hence, to make a loud, sudden noise; to
      detonate; to explode with a violent report.
      [1913 Webster]

   2. To issue or send forth decrees or censures with the
      assumption of supreme authority; to thunder forth menaces.
      [1913 Webster]