Definition of "whinstone" [whin•stone]

• Any of various hard, dark-colored rocks, especially basalt and chert. (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.

• "From this outlet there is a continual descent towards Loch Eitive, and from hence the river Awe pours out its current in a furious stream, foaming over a bed broken with holes, and cumbered with masses of granite and whinstone."
• "Below this mass lies a pale red hardened sandstone, and beneath that a trap-like whinstone."
• "The roads were excellent, and made upon the MacAdam principle, whinstone having been brought for the purpose from the distance of several miles."