tr.v. de·na·tured, de·na·tur·ing, de·na·tures
1. To diminish or alter the nature or natural qualities of.
2. To render unfit to eat or drink without destroying usefulness in other applications, especially to add methanol to (ethyl alcohol).
a. To cause the tertiary structure of (a protein) to unfold, as with heat, alkali, or acid, so that some of its original properties, especially its biological activity, are diminished or eliminated.
b. To cause the paired strands of (double-stranded DNA) to separate into individual single strands.
4. Physics To add nonfissionable matter to (fissionable material) so as to prevent use in an atomic weapon.
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.