Other forms: albumens
The clear, gooey part of an egg that turns white when cooked is called albumen. It's what gives meringues their fluffy texture and cakes their moisture.
The word albumen comes from the Latin word albus, meaning "white." When cooked, an egg's albumen, which surrounds the yolk, turns white. In fact, the albumen of an egg is called the "egg white." Albumen is high in protein. The type of protein in albumen is also called albumen, often spelled albumin. That type of water-soluble protein is in other things, too, like blood, muscle, and milk. In plants, albumen is the nutritive matter inside seeds. The albumen in bird and reptile eggs provides protection and nourishment to the embryo of a fertilized egg.