Where does “acherusius” come from?

acherusius (Latin) comes from Ancient Greek Ἀχερούσιος, from Ancient Greek Ἀχέρων, from Ancient Greek ἄχος, from Proto-Indo-European h₂égʰos, from Proto-Indo-European h₂egʰ- — to be upset, afraid.

acherusius (Latin): of or pertaining to the Acheron (a river in the underworld)

Definitions

of or pertaining to the Acheron (a river in the underworld)

Ancestry of “acherusius”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	Ἀχερούσιος	Acherontic
2	Ancient Greek	Ἀχέρων	lamentation
3	Ancient Greek	ἄχος	distress; pain, ache
4	Proto-Indo-European	h₂égʰos	distress
5	Proto-Indo-European	h₂egʰ-	to be upset, afraid

Every word from Proto-Indo-European h₂egʰ- →Every word from Proto-Indo-European h₂égʰos →Every word from Ancient Greek ἄχος →