Webster's Dictionary 
(n.) The god of the great outer sea, or the river which was believed to flow around the whole earth.
Cyclopedia of Biblical, Theological and Ecclesiastical Literature 
in ancient mythology, war the powerful divinity of the sea (hence the nauie Ocean), which was believed to encircle the earth. According to Hesiod he was the son of Uranus and Gae (heaven and earth). He was married to Tethys, by whom he begot the principal rivers, such as the Alpheus, Peneus, Strymon, etc., with a number of daughters who are called from him Oceanides (q.v.). ‘ According to Homer, Oceanus was the father of all the gods, and on that account he received frequent visits from the rest of the deities. He is generally represented as an old man with a long flowing beard, and sitting upon the waves of the sea. He often holds a pike in his hand, while ships under sail appear at a distance, or a sea-monster stands near him. Oceanus presided over every part of the sea, and even the rivers were subjected to his power. The ancients were superstitious in their worship of Oceanus, and revered with great solemnity a deity to whose care they entrusted themselves when going on any voyage (Hesiod, Theog.; Ovid, Fast. v. 81, etc.; Apollod. i; Cicero, De Nat. D. 3:20; Homer, II.).
The Nuttall Encyclopedia 
n the Greek mythology the great world-stream which surrounds the whole earth, and is the parent source of all seas and streams, presided over by a Titan, the husband of Tethys, and the father of all river-gods and water-nymphs. He is the all-father of the world, as his wife is the all-mother, and the pair occupy a palace apart on the extreme verge of the world.