Oogenesis: The process of egg formation.
The second "o" in oogenesis is pronounced separately from the first: o?o?gen?e?sis. The word was created from the prefix "oo-" (Greek oon, egg) + "genesis" (the coming into being of something) = the coming into being of the egg (the ovum).
Oogenesis is in contrast to spermatogenesis, the process of sperm formation.