azygote
/ˈæzɪɡoʊt/; /ˈæzɪɡɒt/Definitions
1. noun
A cell or organism that develops from a fertilized egg cell without undergoing the usual process of cell division, typically occurring in certain species of animals, such as sea urchins.
“In sea urchin development, the azygote stage is characterized by a single cell that undergoes rapid growth and differentiation.”