in·du·ra·tion (ĭn′də-rāshən, -dyə-)
1. The quality or condition of being hardened.
2. The act or process of becoming hardened.
3. The hardening of a normally soft tissue or organ, especially the skin, due to inflammation, infiltration of a neoplasm, or accumulation of blood.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. 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.