A simple water-soluble protein found in many animal tissues and liquids WordNet 3.0 & Open English WordNet

Albumin is a family of globular proteins, the most common of which are the serum albumins. Wikipedia

Family of globular proteins Wikidata

Any of a class of monomeric proteins that are soluble in water, and are coagulated by heat; they occur in egg white, milk etc; they function as carrier protein for steroids, fatty acids, and thyroid hormones and play a role in stabilizing extracellular fluid volume. Wiktionary

Class of monomeric proteins that are soluble in water. Wiktionary (translation)