In Latin, the fourth principal part of the verb agere, meaning "to do", was actus, which could best be translated as "having been done". Actus has had an outsized influence on the English language, making up a lot of words starting with act-:
Hello! I'm Adam Aleksic, a sophomore studying government and linguistics at Harvard University, where I co-founded the Harvard Undergraduate Linguistics Society. In addition to etymology, I also really enjoy politics, vexillology, geography, board games, conlanging, and law.