Where Did Heretofore Come from?

According to the OED, heretofore resulted from the compounding of the adverb here with tofore, derived from the Old English tóforan, meaning previously or in front of. Its official pronunciation is also worth noting, with the o of -to- being an unstressed schwa sound, giving the whole word a distinctive rhythm.

What does the term heretofore mean?

: up to this time : hitherto heretofore unimaginable possibilities I tell you now what we have heretofore kept secret from you— A. C. Whitehead.

Where did hitherto originate?

hitherto (adv.)

c. 1200, from hither + to.