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tu·fa (tfə, ty-)
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n.
A soft, friable, and porous sedimentary rock consisting of calcium carbonate and formed by the evaporation of water, especially at the mouth of a hot spring or on a drying lakebed. It can also be precipitated by algae or bacteria.
[Obsolete Italian tufa, tufo, from Latin tōfus.]
tu·faceous (-fāshəs) adj.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
 

Indo-European & Semitic Roots Appendices

    Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

    Indo-European Roots

    Semitic Roots

    The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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