n. pl. em·bry·os
a. The collection of cells that has developed from the fertilized egg of a vertebrate animal, before all the major organs have developed.
b. A collection of such cells of a human, especially from implantation in the uterine wall through the eighth week of development.
2. Botany The young sporophytic plant contained within a seed or an archegonium.
3. An organism at any time before full development, birth, or hatching.
4. A rudimentary or beginning stage: an idea that was the embryo of a short story.
[Medieval Latin embryō, from Greek embruon : en-, in; see EN-2 + bruein, to be full to bursting.]
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.