Ne·re·us (nîrē-əs, nîrys′)
A sea god, son of Oceanus and Gaea and father of the Nereids.
[Latin Nēreus, from Greek, perhaps originally back-formation from Nērēïs, sea nymph (taken as Nēreus + -is, feminine patronymic suffix); perhaps akin to Lithuanian nerti, to dive, plunge, and Old Church Slavonic nereti, to go deep inside, hide oneself.]
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.