Where does “rōbustus” come from?

rōbustus (Latin) comes from Latin rōbur, from Latin ruber, from Proto-Italic ruðros, from Proto-Indo-European h₁rudʰrós, from Proto-Indo-European h₁rewdʰ- — red.

Ancestry of “rōbustus”, step by step

Step	Language	Word	Meaning
1	Latin	rōbur	—
2	Latin	ruber	red ; ruddy
3	Proto-Italic	ruðros	red
4	Proto-Indo-European	h₁rudʰrós	red
5	Proto-Indo-European	h₁rewdʰ-	red

Every word from Proto-Indo-European h₁rewdʰ- →

rōbustus — Etymology, Origin & Word History | Etymology Explorer