Definition of "thunderstone" []

• Any of various mineral concretions, such as a belemnite, formerly supposed to be thunderbolts. (noun)
• Archaic A flash of lightning conceived as a stone; a thunderbolt. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "He describes the "thunderstone" as an "agglomeration of brick, soot, unburned coal, and cinder.""
• "Then send out a report that a "thunderstone" had fallen at Stockholm, say --"
• "June 20, 1880, it was reported that a "thunderstone" had struck the house at 180 Oakley Street, Chelsea, falling down the chimney, into the kitchen grate."