germinal disc
nounUK /ˈdʒɜːmɪnəl dɪsk/
US /ˈdʒɜːrmənəl dɪsk/
A tiny spot inside a bird's egg where a baby bird starts to grow.
If you look closely at the yolk, you can see the germinal disc.
RELATED WORDS
OTHER MEANINGS
2. The small round area of cytoplasm on the yolk surface of a fertilized egg where cell division begins.
The germinal disc divides rapidly after fertilization.
3. A flattened region of cells in early embryonic development that gives rise to the embryo proper.
Scientists studied the germinal disc to understand early development.
4. The spot on an egg yolk that indicates whether the egg has been fertilized.
A large germinal disc often means the egg was fertilized.