lifer

Liver comes from Old English lifer, from Proto-Germanic *librō. The word may be related to the Proto-Indo-European root *leyp- (to stick, to smear, to be fat), which would make the liver 'the fat one' or 'the sticky one' — a description that matches the organ's texture. An alternative theory connects it to the word 'life' (Old English līf, from *leiben- 'to remain, to live'), making the liver 'the living one' or 'the organ of life.'

The liver connection to life is not just folk etymology. In ancient Mesopotamia, Babylonian haruspices (diviners) read the future from the livers of sacrificed animals. Clay models of livers, marked with divinatory inscriptions, have been found at archaeological sites dating to ~2000 BCE. The liver was the organ of prophecy because it was believed to be the organ of the soul. Greek physicians from Hippocrates to Galen considered the liver the body's central organ, responsible for producing blood and regulating the four humors.

Anatomically, the liver is the largest internal organ, weighing about 1.5 kilograms in adults. It performs over 500 functions, including detoxification, protein synthesis, bile production, and glycogen storage. The liver is the only internal organ that can regenerate — if up to 75% is removed, the remaining tissue will regrow to full size. This fact was somehow known to the ancient Greeks: the myth of Prometheus has an eagle eating his liver daily, only for it to grow back each night.

The word liver has generated many compounds and idioms. Lily-livered (cowardly — from the belief that a pale liver indicated lack of blood, therefore lack of courage). Liver spots (age spots, which have nothing to do with the liver). Liverwort (a plant thought to resemble a liver). The organ's name has spread through the language like the organ itself spreads through the body — everywhere, doing everything.