Meaning

noun a discharge of lightning accompanied by thunder

noun a sliding bar in a breech-loading firearm that ejects an empty cartridge and replaces it and closes the breech

noun the part of a lock that is engaged or withdrawn with a key

originFrom Middle English bolt, from Old English bolt, from Proto-West Germanic *bolt, from Proto-Germanic *bultaz, perhaps from Proto-Indo-European *bʰeld- (“to knock, strike”). Compare Lithuanian beldu (“I knock”), baldas (“pole for striking”). Akin to Dutch and West Frisian bout, German Bolz or Bolzen, Danish bolt, Swedish bult, Icelandic bolti. The association of thunder and lightning with 'bolts'…

Etymology from Wiktionary, CC BY-SA 3.0