CANCER, in astronomy, one of the twelve signs, represented on the globe in the form of a crab, and thus marked (♋) in books. It is the fourth constellation in the zodiac, and that from which one quadrant of the ecliptic takes its denomination. The reason ge-
nerally assigned for its name as well as figure, is a supposed resemblance which the sun's motion in this sign bears to the crab-fish. As the latter walks backwards, so the former, in this part of his course, begins to go backwards, or recede from us; though the disposition of stars in this sign is by others supposed to have given the first hint to the representation of a crab.