1. One that contributes something, such as money, to a cause or fund.
2. Medicine An individual from whom blood, tissue, or an organ is taken for transfusion, implantation, or transplant.
3. Chemistry An atom, molecule, or ion that provides a part to combine with an acceptor, especially an atom that provides two electrons to form a bond with another atom.
4. Electronics An element introduced into a semiconductor with a negative valence greater than that of the pure semiconductor.
Medicine Used for transfusion, implantation, or transplant: a donor organ.
[Middle English, from Anglo-Norman donour, from Latin dōnātor, from dōnāre, to give; see DONATION.]
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.