You would use the definite article "a" (attached to the end of the word) to say "ETSa" (The ETS). If referring to the band En Tol Sarmiento , fans often just use the name "ETS" without an article in casual speech, though "ETSa" is grammatically correct for "the [band] ETS."
In the Basque language, the correct article for depends on whether you are referring to the acronym or the literal translation of the phrase. ets_guretzat
This is a highly popular Basque ska-rock band. Their 2022 album and title track, "Guretzat" , marked a shift toward a more pop-oriented sound. You can listen to the track on Spotify or watch the official videos on the ETS YouTube channel. You would use the definite article "a" (attached