Where does “feijoo” come from?

feijoo (Old Portuguese) comes from Latin phaseolus, from Latin phaselus, from Ancient Greek φάσηλος — cowpea.

Ancestry of “feijoo”, step by step

Step	Language	Word	Meaning
1	Latin	phaseolus	A type of bean with an edible pod; in Antiquity:...
2	Latin	phaselus	a kind of bean with an edible pod, French bean,...
3	Ancient Greek	φάσηλος	cowpea

feijoo — Etymology, Origin & Word History | Etymology Explorer