The phrase "enucleated egg" refers to the process of removing the nucleus, which contains genetic material, from an egg cell. This is usually done for scientific or medical purposes. Full definition
A team in the laboratory of Atsuo Ogura at the National Institute of Infectious Diseases in Shinjuku, Tokyo, cloned 12 mice by removing nuclei from testis cells and inserting them into enucleated egg cells. (sciencemag.org)
They injected intact nuclei from the last living ibex into more than 400 enucleated eggs of the domestic goat. (discovermagazine.com)
The resulting cells are themselves fused with other enucleated egg cells. (scientificamerican.com)