Where does “ache” come from?

ache (Old French) comes from Latin apium, from Latin Apis, from Ancient Greek Ἄπις, from Coptic ϩⲁⲡⲉ, from Egyptian ḥp — the god Apis.

Ancestry of “ache”, step by step

ache traces back through two separate lines of ancestry.

Step	Language	Word	Meaning
1	Latin	apium	parsley; celery; genitive plural of apis
2	Latin	Apis	A seaport town of Egypt situated at the borders with Marmarica
3	Ancient Greek	Ἄπις	—
4	Coptic	ϩⲁⲡⲉ	the Apis bull, a bull worshipped as a herald of the gods (first Ptah, then Osiris, then Atum)
5	Egyptian	ḥp	the god Apis

Step	Language	Word	Meaning
1	Vulgar Latin	acca	aitch; The name of the letter H
2	Latin	ha	The name of the letter "H"; expressing joy or...