Where does “τριάκοντα” come from?

τριάκοντα (Greek) comes from Ancient Greek τριάκοντα, from Proto-Indo-European tridḱómt, from Proto-Indo-European tri-, from Proto-Indo-European tréyes — three.

τριάκοντα (Greek): Katharevousa form of τριάντα

Definitions

Katharevousa form of τριάντα

Ancestry of “τριάκοντα”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	τριάκοντα	thirty
2	Proto-Indo-European	tridḱómt	thirty
3	Proto-Indo-European	tri-	three, threefold
4	Proto-Indo-European	tréyes	three

Every word from Proto-Indo-European tréyes →Every word from Proto-Indo-European tri- →Every word from Proto-Indo-European tridḱómt →