I'm watching the old 4-6 Star Wars films and I'm noticing something; the word or term "Sith" is never mentioned at all. In fact, Darth Vader isn't referred to as anything but a member of the Imperials.

Was Darth Vader a Sith Lord? Also, was the term Sith ever used in the original trilogy at all? Where did it first come up?

The term Sith is so frequently used today to discuss Star Wars; you can almost never have a discussion about a Star Wars game these days without using the term Sith.

Well he was referred to as Lord Vader which implies that he was a Sith Lord. IMO.

Short answer: yes.

From what I know, there are two sith: a Sith Master and his apprentice, who probably becomes a Sith Lord. I think it's fair to say Darth Vader was a Sith Lord

Vader was a Sith Lord, I'm positive of it. Palpatine was his master, also called Darth Sidious. Darths have their underlings and since Vader was Sidious' Apprentice, he had to have been Sith Lord.

However, Siths were never mentioned in the original trilogy. The most we get is " yep, these guys have red lightsabers and are bad, bad folk but you are a Jedi, Luke, like your father! These bad seeds you're fighting against have no other name and nothing to do with your father! Go on now, strike them down! "

I believe the term Sith was simply thought of after the original trilogy. Lucas, if I remember correctly, just sort of wove the term into the stories afterward, those written and formed before the Phantom Menace that is.

Edit: Also Palpatine, at the end of the Revenge of the Sith, christens the rebuilt Anakin as " Lord Vader ".

As I understand it, the rule of two established by Darth Bane allows for one master, and one apprentice, but both have the mantle of "dark lord of the sith."

So yes.

Disclaimer: my understanding may not be complete or correct.

Nope---was an average guy with a lazer sword .

He bought it in a bar.

After the Emperor forms the galactic empire, they pretty much drop the name sith. But anyone with darth in their name is a sith lord.

The novelization of A New Hope, written by Lucas and published in '76, describes Vader as a Dark Lord of the Sith in the first or second paragraph about him.

Is that what you were looking for?

That's exactly what I was looking for, thank you!

I thought he got it from a vendor at an amusemant park...the guy that sells the glow necklaces and blinky things and such.