Cancer, both the disease and the astronomical constellation, derive from the Latin cancer or cancrum, meaning crab. The astrological sign, of course, is said to resemble a crab and the disease was so named by the ancient Greek physician Galen (129-200 A.D.) who noted the similarity between a certain type of tumor with a crab as well—the swollen veins around the tumor resembling the legs of a crab.
Old English adopted cancer directly from Latin and used it for a variety of spreading sores and ulcers. This early sense survives in the modern word canker. From c.1000 in a manuscript called Læce Boc (Leech Book), collected in Oswald Cockayne’s Leechdoms, Wortcunning, and Starcraft of Early England, Vol. II, 1865:
Gemeng wið þam dustum, clæm on ðone cancer.
(Mix with the dust, smear on the cancer.)
And from Wyclif’s 2 Timothy, 1382:
The word of hem crepith as a kankir
The word was being applied specifically to the disease we today call cancer by the beginning of the 17th century. From Philemon Holland’s translation of Pliny’s Historie of the World:
Cancer is a swelling or sore comming of melancholy bloud, about which the veins appeare of a blacke or swert colour, spread in manner of a Creifish clees.
The astronomical sense of cancer is from the Latin name for the constellation of the crab. The name was known to the Anglo-Saxons, but only as a Latin name and was not assimilated into English until the Middle English period. It appears in Ælfric’s De Temporibus Anni, written c.993, in a list of the constellations of the Zodiac:
Feorða • Cancer • þæt is Crabba
(Fourth, Cancer, that is the crab.)
The Anglicized name appears c.1391 in Chaucer’s Treatise on the Astrolabe:
In this heved of cancer is the grettist declinacioun northward of the sonne...this signe of cancre is clepid the tropik of Somer.
(At this first point (head) of cancer is the greatest declination northward of the sun…this sign of cancer is named the tropic of summer.)
(Source: Oxford English Dictionary, 2nd Edition)
Copyright 1997-2015, by David Wilton