The word "protein" is from the Greek word "protos", meaning "of primary importance". It was first used in 1838 by the Swedish chemist Jons Jakob Berzelius. He used the word protein to describe large organic compounds with almost equivalent empirical formulae, and chose this name because of the primary importance of these compounds for animal nutrition. It would take the science of the twentieth century to fully elucidate the primary importance to life of these diverse and fascinating macromolecules.