Heretofore means `before this time' or `up to now'. They reported that clouds are an important and heretofore uninvestigated contributor to the climate. = hitherto, previously. before this time (here + tofore (11-17 centuries) (from toforan))
used in negative statement to describe a situation that has existed up to this point or up to the present time; "So far he hasn't called"; "the sun isn't up yet"