Definition of "flowstone" [flowstone]

• A layered deposit of calcium carbonate on rock where water has flowed or dripped, as on the walls of a cave. (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.

• "Another guide also turned off the lights in another room to show visitors the dim phosphorescense from a "flowstone" formation."
• "Portions were rocky with slides or jacketed in flowstone."
• "Suspended in the flowstone beneath her feet, a dozen dead hadals seemed ready to rise up and break free."