1. A sheet of water flowing over a dam or similar structure.
2. Geology A large sheetlike body of rock that has been moved far from its original position.
3. Mathematics Either of the two parts into which a cone is divided by the vertex.
[French, tablecloth, nappe, from Old French, tablecloth, from Latin mappa, napkin; see MAP.]
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:
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.