What does "thunderbolt" mean?

Thunderbolt: Something resembling lightning in suddenness and effectiveness. The Scipios' worth, those thunderbolts of war. Dryden.

Additional senses

  1. 2.Vehement threatening or censure; especially, ecclesiastical denunciation; fulmination. He severely threatens such with the thunderbolt of excommunication. Hakewill.
  2. 3.(Paleon.) A belemnite, or thunderstone. Thunderbolt beetle (Zoöl.), 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.

Sources