Isis

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Mythology An ancient Egyptian goddess of fertility, the sister and wife of Osiris.
2. The upper Thames River in south-central England in the vicinity of Oxford. The name is used locally and in literature.

Century Dictionary and Cyclopedia

1. n. In Egypt. myth., the chief female deity; the sister, wife, and counterpart or female form of Osiris, and the mother of Horus. She is distinguished by the solar disk and cows' horns on her head, often surmounted by a diminutive throne, and bears the lotus scepter. By the Greeks she was identified with Io. Her worship in a modified form, as a nature-goddess, was introduced subsequently to the Alexandrine epoch into Greece, and was very popular at Rome from the end of the republic. The Greek and Roman priests and priestesses of Isis wore a special costume, and had as an attribute a peculiar metallic rattle, the sistrum.
2. n. The typical genus of the family Isidæ.

Wiktionary

1. n. Egyptian mythology A complex ancient Egyptian goddess. Wife of Osiris and mother of Horus. Worshiped as the ideal mother and wife as well as the matron of nature and magic.
2. n. UK The River Thames.

GNU Webster's 1913

1. n. (Myth.) The principal goddess worshiped by the Egyptians. She was regarded as the mother of Horus, and the sister and wife of Osiris. The Egyptians adored her as the goddess of fecundity, and as the great benefactress of their country, who instructed their ancestors in the art of agriculture.
2. n. (Zoöl.) Any coral of the genus Isis, or family Isidæ, composed of joints of white, stony coral, alternating with flexible, horny joints. See Gorgoniacea.
3. n. (Astron.) One of the asteroids.

WordNet 3.0

1. n. Egyptian goddess of fertility; daughter of Geb; sister and wife of Osiris