Old game, not new, that could generate life (4)
I believe the answer is:
ovum
'old game not new that could generate life' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
This is all the clue.
Can you help me to learn more?
(Other definitions for ovum that I've seen before include "Reproductive cell, 'egg' in Latin" , "Female gamete" , "A female egg-cell" , "Female reproductive cell" , "bit of life potentially" .)