1. Abbr. oc. The entire body of salt water that covers more than 70 percent of the earth's surface.
2. Often Ocean Abbr. O, O., Oc. Any of the principal divisions of the ocean, including the Atlantic, Pacific, and Indian oceans, their southern extensions in Antarctica, and the Arctic Ocean.
3. A great expanse or amount: "that ocean of land which is Russia" (Henry A. Kissinger).