Rahu (Sanskrit) The seizer; a daitya supposed to seize the sun and moon and thus cause eclipses. “A giant, a Demi-god, the lower part of whose body ended in a Dragon or Serpent’s tail. During the churning of the Ocean, when the gods produced amrita — the water of Immortality — he stole some of it, and drinking, became immortal.
The Sun and Moon, who had detected him in his theft, denounced him to Vishnu, who placed him in the stellar spheres, the upper portion of his body representing the Dragon’s head and the lower (Ketu) the Dragon’s tail; the two being the ascending and descending nodes.
Since then, Rahu wreaks his vengeance on the Sun and Moon by occasionally swallowing them. But this fable had another mystic meaning, since Rahu, the Dragon’s head, played a prominent part in the mysteries of the Sun’s (Vikarttana’s) initiation, when the candidate and the Dragon had a supreme fight” (SD 2:381).
