Where does “tetracos-” come from?
tetracos- (English) comes from Ancient Greek εἴκοσι, from Proto-Hellenic ewīkəti, from Proto-Indo-European wídḱm̥ti, from Proto-Indo-European dwidḱómt, from Proto-Indo-European déḱm̥t — ten.
Ancestry of “tetracos-”, step by step