Where did sith come from

From where did people get the idea that vader was a sith rather than a dark jedi.

The word "sith" was not used even once in the original trilogy, and the emperor looked nothing like the typecast sith lords in the "tales of the jedi" series.

The novel of Phantom Menace calls Darth Sidious (Empereor to be) and Darth Maul, "the Sith."

"Tales of the jedi" takes place a looooooong time ago. Nobody looked like the characters in the movies in those comics. The Sith in KotOR, for example, don't look anything like the Sith from Tales of the Jedi either. The Sith in there aren't what most people typically think of as Sith; that's because they're so ancient. In fact, I think that was even before Sith lords were called "Darth". Which brings me to this... Vader is Sith. He was the apprentice, Sidious was the master. Furthermore, all Sith lords from a certain point (though I can't tell you what that is), are called Darth Somethingorother. Ordinary dark jedi are not. So, Vader was a fallen jedi who became a Sith lord.

i believe the sith are a people...a slave race to the Lords of the Sith....dark jedi who used the force to control the sith....

I know that.
What I meant to ask was, how did people become aware of the term "sith" when the original trilogy was released?
(as it was not used in the original trilogy)

like I said...somebody made it up....it appeared in old comic books and such....new terms and species are made up all the time....

cause Darth means dark lord of the sith and darth was used a couple of times in the OT 😉 😛