Lactalbumin

Part of speech: noun

Definitions

1. A protein found in the whey of milk, important for nutrition and often used in food products and supplements
2. A soluble milk protein that separates into the watery whey during cheese making and is rich in essential amino acids
3. Any of the globular proteins present in mammalian milk, valued for their nutritional content and use in foods

Etymology: Lactalbumin is a protein found in milk, and its name is built from two parts that each carry their own history. The first part, "lacto-", comes from Latin "lac" (genitive "lactis"), meaning milk, and it appears in many scientific terms about milk, such as "lactose" and "lactic". The second part, "albumin", comes from Latin "albumen", meaning egg white, which is related to "albus", meaning white. English scientists took that old word for the white of an egg and applied it to a whole family of soluble proteins, so a term first tied to eggs ended up naming a protein in milk. The combination is a plain technical coinage: a milk prefix attached to a protein name, assembled when scientists needed a label for the whey protein they were isolating. Its meaning follows directly from its parts, so the word tells you exactly what it is: a white-egg-type protein from milk.