What does hēphaestītis mean in Latin?

hēphaestītis, a noun, means “An unknown precious stone”.

What is the genitive of hēphaestītis?

The genitive singular is hēphaestītidis. hēphaestītis is feminine, third declension.

In classical Latin, [heː.pʰae̯sˈtiː.tɪs]; in ecclesiastical (church) Latin, [e.fesˈtiː.tis].

noun · femininethird declension

hēphaestītis f (genitive hēphaestītidis)

Classical[heː.pʰae̯sˈtiː.tɪs]Ecclesiastical[e.fesˈtiː.tis]

hēphaestītis, ĭdis, f., = ἡφαιστῖτις,

I. a precious stone, otherwise unknown, Plin. 37, 10, 60, § 166.

Borrowed from Ancient Greek ἡφαιστῖτις (hēphaistîtis), from Ἥφαιστος (Hḗphaistos, “Hephaestus”) + -ῑ́της (-ī́tēs).