Other forms: prehistorically
If while hiking, you see strange painting on a cliff, it may be rock art from prehistoric times, meaning something from the time before history was recorded.
When you break down the word prehistoric, it’s easy to figure out what it means. The prefix pre-, means “before” and historic relates to something from a past culture. Put the two together, and you get prehistoric, a word that describes something that comes from a time before history was recorded. For example, Stonehenge is a prehistoric site, or the woolly mammoth is a prehistoric beast.