THE ETERNAL is one of the many, many translations for יהוה – a mostly untranslatable Hebrew divine moniker or “theonym” (which term I just now learned – thank you, Wikipedia!) connected with a form of the cognate “to be.” It appears in the Torah (Exodus 3:15) right after another theonym, אֶֽהְיֶ֖ה אֲשֶׁ֣ר אֶֽהְיֶ֑ה (“Ehyeh Asher Ehyeh,” or “I Will Be What I Will Be”) in Ex. 3:14, where Moses asks G?d what Name to tell the enslaved Jews who will question his authority to speak on G?d’s behalf. “The Eternal” takes the “to be” ball and runs with it, in the sense/concept of G?d existing forever and ever, outside of spacetime, infinite and unknowable. (We could get all mystical and Qabalistic at this point, nattering on about lofty Ain Sof (transcendence) v. folksy Shekhina (immanence), but let’s save that for another time – no pun intended.)
This is one of my favorite Names for that-which-some-people-call-God: some are creative, others traditional, each unique. If you want to see your favorite here, but haven’t, send it along with the subject line “365 Names” and let us know whether or not you want to be credited.