Yes, ocean is in the scrabble dictionary

Ocean Definition

noun

A great expanse or amount: "that ocean of land which is Russia” ( Henry A. Kissinger).

Any of the principal divisions of the ocean, including the Atlantic, Pacific, Indian, Arctic, and Antarctic oceans.

A very large or unlimited space or quantity.

Any of the large bodies of water (as the Atlantic Ocean) into which the great ocean is divided.

The whole body of salt water that covers nearly three fourths of the surface of the earth.