\Thun"der*bolt`\, n.
1. A shaft of lightning; a brilliant stream of electricity
   passing from one part of the heavens to another, or from
   the clouds to the earth.
2. Something resembling lightning in suddenness and
   effectiveness.
         The Scipios' worth, those thunderbolts of war.
                                               --Dryden.
3. Vehement threatening or censure; especially,
   ecclesiastical denunciation; fulmination.
         He severely threatens such with the thunderbolt of
         excommunication.                      --Hakewill.
4. (Paleon.) A belemnite, or thunderstone.
{Thunderbolt beetle} (Zo["o]l.), a long-horned beetle
   ({Arhopalus fulminans}) whose larva bores in the trunk of
   oak and chestnut trees. It is brownish and bluish-black,
   with W-shaped whitish or silvery markings on the elytra.