primordium
/praɪˈmɔrdiəm/
noun
- The earliest stage of development of an organ or part in an embryo or plant.
- In the embryo, the heart primordium begins to form just a few weeks after conception.
- The leaf primordium appears as a small bump on the growing tip of the plant.
- Biologists observed the primordium of the wing in the developing chick.
Synonyms