what does "Sadducismus Triumphatus"mean?
The Confession of Margaret Jackson, relict of Tho. Stuart in Shaws, who being examined by the Justices anent her being guilty of Witchcraft, declares…That forty years ago, or thereabout, she was at Pollockshaw-croft, with some few sticks on her back, and that the black Man came to her, and that she did give up herself unto the black Man, from the top of her head to the sole of her foot; and that this was after the Declarant’s renouncing of her Baptism; and that the Spirit’s name, which he designed her, was Locas. And that about the third or fourth of January, instant, or thereby, in the night-time, when she awaked, she found a Man to be in bed with her, whom she supposed to be her Husband; though her Husband had been dead twenty years, or thereby, and that the Man immediately disappeared: And declares, That this Man who disappeared was the Devil.

——Joseph Glanvil: Sadducismus Triumphatus

Question

what does "Sadducismus Triumphatus"mean?
The Confession of Margaret Jackson, relict of Tho. Stuart in Shaws, who being examined by the Justices anent her being guilty of Witchcraft, declares…That forty years ago, or thereabout, she was at Pollockshaw-croft, with some few sticks on her back, and that the black Man came to her, and that she did give up herself unto the black Man, from the top of her head to the sole of her foot; and that this was after the Declarant’s renouncing of her Baptism; and that the Spirit’s name, which he designed her, was Locas. And that about the third or fourth of January, instant, or thereby, in the night-time, when she awaked, she found a Man to be in bed with her, whom she supposed to be her Husband; though her Husband had been dead twenty years, or thereby, and that the Man immediately disappeared: And declares, That this Man who disappeared was the Devil.

——Joseph Glanvil: Sadducismus Triumphatus

Answer

The phrase in question is not English, it is Latin. Latin was the liturgical language of Old, Middle and Early Modern (Shakesphearean) English society.

(*It should be noted:
The text in general is archaic, its still modern English but noone talks like this anymore.)

Latin had a huge influence on English during its developement and although English did have many latin loan words, this is not one of them. This is a direct passage from the Latin language.

Answer

As a native speaker, here's how I'd approach this. The typography of the line tells me that the first part is a quotation, and that "Joseph Glanvil: Sadducismus Triumphatus" is the source of the quotation.

I recognize "Joseph" as a common English first name. "Glanvil" sounds like a surname. The colon (the punctuation mark with two dots, : ) is often used to separate author and title.

Therefore, I assume this is a quotation from and author named Joseph Glanvil, in a word entitled "Sadducismus Triumphatus."

The pattern of the words and words endings makes me think the words are in Latin, and I know that Latin was a common language in the 1600s when people believed in witchcraft.

I also know that in the Bible, the Sadducees were enemies of Jesus, and "Triumphatus" sounds like "triumph," so I guess that the title means something like "Sadducee-ism Triumphant."

And at that point I would need to look it up. It is not a famous or well-known work. Can you access Wikipedia easily? You can read the Wikipedia article for yourself:

https://en.wikipedia.org/wiki/Saducismus_Triumphatus

Answer

Wikipedia says
Saducismus triumphatus[1] is a book on witchcraft by Joseph Glanvill, published posthumously in England in 1681.
https://en.wikipedia.org/wiki/Saducismus_Triumphatus
The book seems to be available at
https://archive.org/details/saducismustriump00glan/page/n8/mode/2up
Note that the original text has only one "d" in Saducismus as you'd expect from Latin.
.
Sorry my Latin was never good enough to translate what it means.