Epigenetics
What is the name for a single fertilized egg?
Botany
Voice for Life Hyalin Egg white Egg Twin
Voice_for_Life-Abstract Hyalin-Abstract Egg_white-Abstract Egg-Bird_eggs Twin-Monozygotic_("identical")_twins
Voice for Life is a New Zealand pro-life advocacy group. Voice for Life's advocates the humanity of the fertilized egg, embryo, and foetus and making abortion medical homicide. 
Hyalin is a protein released from the cortical granules of a fertilized animal egg. The released hyalin modifies the extracellular matrix of the fertilized egg to block other sperm from binding to the egg, and is known as the slow-block to polyspermy. All animals have this slow-block mechanism. 
Egg white is the common name for the clear liquid (also called the albumen or the glair/glaire) contained within an egg. In chickens it is formed from the layers of secretions of the anterior section of the hen's oviduct during the passage of the egg. It forms around either fertilized or unfertilized egg yolks. The primary natural purpose of egg white is to protect the yolk and provide additional nutrition for the growth of the embryo (when fertilized). Egg white consists primarily of about 90% water into which is dissolved 10% proteins (including albumins, mucoproteins, and globulins). Unlike the yolk, which is high in lipids (fats), egg white contains almost no fat, and carbohydrate content is less than 1%. Egg whites contain just over 50% of the protein in the egg. Egg white has many uses in food (e.g. mousse) and also many other uses (e.g. in the preparation of vaccines such as those for influenza). 
Bird eggs are laid by females and incubated for a time that varies according to the species; a single young hatches from each egg. Average clutch sizes range from one (as in condors) to about 17 (the Grey Partridge). Some birds lay eggs even when not fertilized (e.g. hens); it is not uncommon for pet owners to find their lone bird nesting on a clutch of unfertilized eggs, which are sometimes called wind-eggs. 
Monozygotic (MZ) or identical twins occur when a single egg is fertilized to form one zygote (hence, "monozygotic") which then divides into two separate embryos. 