n. |
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
n. A tough, silicified limestone formerly used to make millstones. It is typified by the presence of multiple cavities that originally housed fossilized shells. |
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.







