Henceforth is defined as starting now.
When you change your name from Smith to Jones after you get married, this name change is an example of when you might say 'Henceforth, I shall be called Jones."
- from this time onalso hence·for′ward
- thereafter; subsequently
Origin of henceforthMiddle English hennesforth: see hence and forth
From this time forth; from now on.
- (formal) From now on; from this time on.
- I will try to do a better job, henceforth, now that I know the proper technique!