ocean

1 the whole body of salt water that covers nearly three-fourths of the earth <the ocean still holds mysteries that we are only beginning to unravel> Synonyms blue, brine, deep, Neptune, sea, seven seas Related Words blue water, high seas, main, waters; basin; Davy Jones's locker, depths

2 an immeasurable depth or space <with a single bound from top of the cliff, he propelled the hang glider into the ocean of air over the valley> Synonyms abysm, chasm, deep, gulf, abyssRelated Words cleft, crevasse, crevice, fissure; cavern, hole, hollow, pit; breadth, expanse, extent, reach, spread, stretch; black hole, emptiness, nothingness, vacancy, vacuity, vacuum, void