IPA: /hɛnsˈfɔːθ/
KK: /hɛnsˈfɔrθ/
From this time onward; starting now and continuing into the future.
The rules will apply henceforth, so everyone must follow them.
Henceforth → It is formed from "hence" (from Old English "hence", meaning from this place or time) and "forth" (from Old English "forð", meaning forward or onward). The word "henceforth" means from this time onward or from this point forward.
Think of 'from this place' ('hence') and 'forward' ('forth') to remember that 'henceforth' means from this time onward.