The et meaning depends on whether you are treating it as a word or an abbreviation. Et as a word comes from a Latin conjunction that means, “and.” You can see it in the phrase, “et al.” which means “the rest.” This phrase is used when you want to shorten a long list of authors in a citation. There is more than one ET definition when these letters are used as an abbreviation. In astronomy, the ET meaning refers to an extraterrestrial. This abbreviation was made famous in the 1982 film about an alien lifeform directed by Steven Spielberg. A less dramatic ET definition can be found when it is used as an abbreviation for Eastern Time. When someone asks you, "What is ET?", you can tell them the time in New York City.
(in North America) Eastern time.
Egypt (international vehicle registration).