Use 'henceforth' when announcing decisions that will affect the future. Henceforth, meetings will start at 9 AM.
Pro Tip 2/3
Serious Tone
'Henceforth' adds a formal and serious tone to statements. Henceforth, you must submit your assignments on time.
Pro Tip 3/3
Not for Past
Avoid 'henceforth' for past events; it's about what happens from this moment onwards. Incorrect: He was henceforth known for his bravery. Correct: He will henceforth be known for his bravery.