Viewing a history listing
Unknown; good question. I'll see if I can find an authoritative (hah) answer.
In the meantime, I'll just say that this /probably/ means that a name (which "Authority" awkwardly describes here) comes from the source that created the synonym in the first place, and should be considered authoritative. So I suppose you might say this 'authority' refers to 'the original source of this name'.
This is one of those words that comes from our content partners and thus we /cannot/ change it, so we sort of have to "make do" with translating it as best we can. Sorry.