Where does “kastanha” come from?

kastanha (Nheengatu) comes from Portuguese castanha, from Old Portuguese castanna, from Latin castanea, from Ancient Greek καστάνεια, from Ancient Greek κᾰ́στᾰνᾰ — sweet chestnuts; chestnut.

kastanha (Nheengatu): brazil nut (Bertholletia excelsa)

Definitions

brazil nut (Bertholletia excelsa)

Ancestry of “kastanha”, step by step

Step	Language	Word	Meaning
1	Portuguese	castanha	chestnut; feminine singular of castanho
2	Old Portuguese	castanna	—
3	Latin	castanea	a chestnut tree; a chestnut
4	Ancient Greek	καστάνεια	Alternative form of κᾰ́στᾰνᾰ; chestnut
5	Ancient Greek	κᾰ́στᾰνᾰ	sweet chestnuts; chestnut

Every word from Ancient Greek κᾰ́στᾰνᾰ →Every word from Ancient Greek καστάνεια →Every word from Latin castanea →