epithēlium (New Latin) comes from Ancient Greek ἐπί, from Ancient Greek Ἡμέρα, from Ancient Greek ἦμαρ, from Proto-Hellenic ā́mər, from Proto-Indo-European h₂eh₃mr̥, from Proto-Indo-European h₂eh₃- — to be hot; to burn.
Ancestry of “epithēlium”, step by step
epithēlium traces back through two separate lines of ancestry.