Can someone tell me which word—"thenceforth" or "thenceforward"—is more modern? Thanks. They are synonyms, are they not?
Online Etymology Dictionary gives thenceforth dating from the 14th century and thenceforward dating from the 15th century; hence, off that data, I would say thenceforward is the more modern of the two. And yes, they are synonyms.
I agree that they're synonyms in terms of denotation, but in the vein of "there are no true synonyms" I will point out that Google ngrams confirms my impression that henceforth is much more commonly used (at all times except for a weird peak in the early 17th century). So depending on the effect you're trying to create... henceforth will likely feel more natural and expected to your reader, which may be good or bad. ETA: And after correcting @jannert, I notice that I was referring to the wrong words, too - I used hence instead of thence. Result is pretty much the same: -forth is much more common than -forward. But there's no weird 17th century peak for the thence. Phew. This is getting confusing!
I don't think 'henceforth' and 'thenceforth' are quite the same. The implication in the definitions I looked up indicates that 'henceforth' means 'from this time forward,' but it's from the present time. A modern equivalent of henceforth would be 'from now on'—as in: "henceforth, we will no longer accept cash; you will need a credit card." Thenceforth, however, indicates the event is in the past. "The automobile became a common mode of transportation in the early twentieth century; thenceforth a team of horses and a carriage was no longer a common sight on our roads." The modern equivalent of thenceforth would be 'from then on.'
I agree, but... those aren't the words. We're looking at thence- for both, and then either forth or forward.
I would also add that though thenceforward is technically the "younger" of the two, this does not mean that it overtook and supplanted thenceforth. It may have had a few minutes in the sun as a novelty and then faded. I say this only because I work as a legal translator and I am perfectly aware of thenceforth because - while archaic in common parlance - it remains hale and hearty in the realms of legalese where brevity* and exactitude are of the essence. I have never come across thenceforward, though, in my work. *Legalese is typically seen as longwinded and often baroque, not concise, but without such terms as thenceforth, henceforth, herein, therein, heretofore, theretofore, etc., which have long since waned in common use, it would be unthinkably worse.