Where does “plu” come from?

plu (Esperanto) comes from Latin plūs, from Old Latin plous, from Proto-Indo-European ploh₁is-.

plu (Esperanto): further, longer, more

Definitions

Step	Language	Word	Meaning
1	Latin	plūs	—
2	Old Latin	plous	—
3	Proto-Indo-European	ploh₁is-	—

plu — Etymology, Origin & Word History | Etymology Explorer