canker

Canker is commonly known as the name for a type of spreading sore that eats into the tissue-a use that obviously furnished the verb with both its medical and figurative senses. The word ultimately traces back to Latin cancer, which can refer to a crab or a malignant tumor. The Greeks have a similar word, "karkinos," and according to the Ancient Greek physician Galen the tumor got its name from the way the swollen veins surrounding the affected part resembled a crab's limbs. "Cancer" was adopted into Old English, becoming "canker" in Middle English and eventually shifting in meaning to become a general term for ulcerations. "Cancer" itself was reintroduced to English later, first as a zodiacal word and then as a medical term.