Where does “castan” come from?

castan (Manx) comes from Old Irish castán, from Old French chastaigne, from Old English ċisten, from Latin castanea, from Ancient Greek καστάνεια, from Ancient Greek κᾰ́στᾰνᾰ — sweet chestnuts; chestnut.

castan (Manx): chestnut

Definitions

chestnut

Ancestry of “castan”, step by step

Step	Language	Word	Meaning
1	Old Irish	castán	—
2	Old French	chastaigne	chestnut
3	Old English	ċisten	chestnut
4	Latin	castanea	a chestnut tree; a chestnut
5	Ancient Greek	καστάνεια	Alternative form of κᾰ́στᾰνᾰ; chestnut
6	Ancient Greek	κᾰ́στᾰνᾰ	sweet chestnuts; chestnut

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