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