1. The entire body of salt water that covers more than 70 percent of the earth's surface.
2. Abbr. Oc. or O. Any of the principal divisions of the ocean, including the Atlantic, Pacific, Indian, Arctic, and Southern Oceans.
3. A great expanse or amount: "that ocean of land which is Russia" (Henry A. Kissinger).
[Middle English occean, from Old French, from Latin ōceanus, from Greek Ōkeanos, the god Oceanus, a great river encircling the earth.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.