“Note on the meaning of scientific terminology for human development: “Organism” is the scientific name for a living human being. Only organisms undergo development. “Zygote” is the one-cell human organism produced by sperm-egg fusion. “Embryo” is a human organism during the first eight weeks of development”5
5Condic, M.L., The Origin of Human Life at Fertilization: Quotes Compiled from Medical Textbooks and Peer-Reviewed Scientific Literature, Bioethics Defense Fund, 2017, https://bdfund.org/wp-content/uploads/2016/05/Condic-Sources-Embryology.pdf-old.