Looked into it, seems I was misremembering:
Her actual familial relation in the comics is more or less entirely unknown.
She's simply assumed to be Morticia's mother in the comics because she has a last name there that isn't Addams, but the family at the time didn't actually have an established last name(in the comics, they never really had, I believe).
They were "The Addams Family" not by name back then, but because they were the family drawn by Charles Addams. Heck, even the name "The Addams Family" wasn't his invention(he used "His Evils/Addams's Evils") but the medias nickname for them.
But yes, Gomez's mother in the TV series.