Where does “treintavo” come from?

treintavo (Spanish) comes from Spanish treinta, from Old Spanish treyenta, from Latin trīgintā, from Proto-Indo-European tridḱómt, from Proto-Indo-European tri-, from Proto-Indo-European tréyes — three.

treintavo (Spanish): thirtieth

Definitions

thirtieth

Ancestry of “treintavo”, step by step

Step	Language	Word	Meaning
1	Spanish	treinta	thirty
2	Old Spanish	treyenta	—
3	Latin	trīgintā	thirty; 30
4	Proto-Indo-European	tridḱómt	thirty
5	Proto-Indo-European	tri-	three, threefold
6	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 →