cross-posted from: https://quokk.au/c/sigh_fi/p/1040544/can-i-copy-your-homework
While the characters in early episodes of Stargate SG-1 often referred to a group of mysterious aliens by using terms like "the gate-builders", I believe the first time those aliens were referred to as "the Ancients" was in S2E16 "The Fifth Race" in 1998. As far as I can tell, the first time the Ancients were brought up on Farscape was S1E16 "A Human Reaction" in 1999. Even if you assume the idea was planned from the very beginning of Farscape, the first episode still aired in 1999, months after the Ancients had been established in Stargate.
I seem to remember there was some artifact or something inscribed with the words "property of the Ancients" (or some Ancient phrase to that effect), illustrating that they did literally call themselves that after abandoning Atlantis.
I guess it depends on how far after that was?
They were called Alterans when living in Atlantis (Ori elsewhere), if the inscription was made centuries or millenia later by the last vestiges of their culture (like someone who spent 100k years in a stasis pod) then they might refer to their own culture by the contemporary name of ancients?
Maybe the writers were just lazy by that point?
All were really doing is rationalizing what they made up and then only what made it to the show anyways.
For bonus points:
I had to check the wiki to be sure and this is the quote:
https://stargate.fandom.com/wiki/Ancient