Where does “Anguila” come from?

Anguila (Portuguese) comes from Italian anguilla, from Latin anguilla, from Proto-Italic *anɣʷis, from Proto-Indo-European h₂éngʷʰis — snake.

Ancestry of “Anguila”, step by step

Step	Language	Word	Meaning
1	Italian	anguilla	eel
2	Latin	anguilla	eel; small snake; vocative singular of anguilla
3	Proto-Italic	*anɣʷis	—
4	Proto-Indo-European	h₂éngʷʰis	snake

Anguila — Etymology, Origin & Word History | Etymology Explorer