from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A tough, silicified limestone formerly used to make millstones. It is typified by the presence of multiple cavities that originally housed fossilized shells.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Alternative spelling of burrstone.
from the GNU version of the Collaborative International Dictionary of English
- n. A cellular, flinty rock, used for mill stones.
from The Century Dictionary and Cyclopedia
- n. See burstone.
Variant of burr1 + stone.(American Heritage® Dictionary of the English Language, Fourth Edition)