What does Anna mean in Latin?

Anna, a proper noun, means “a female given name, equivalent to English Ann”.

What is the genitive of Anna?

The genitive singular is Annae. Anna is feminine, first declension.

In classical Latin, [ˈan.na]; in ecclesiastical (church) Latin, [ˈan.na].

proper noun · femininefirst declension

Anna f sg (genitive Annae)

Classical[ˈan.na]Ecclesiastical[ˈan.na]

femininesingulara female given name, equivalent to English Ann
Anno Regni Annæ Reginæ Magnæ Brittaniæ, Franciæ, & Hiberniæ, Decimo.Twelfth regnal year of Queen Anne of Great Britain, France, and Ireland.1711, Anno Regni Annæ Reginæ Magnæ Brittaniæ, Franciæ, & Hiberniæ, decimo.:

Anna, ae, f., (cf. Gesen. Gesch. Hebr. Spr. p. 228),

I. the sister of Dido, Verg. A. 4, 9 et saep.; Ov. H. 7, 191; Sil. 8, 55 al.

From Ancient Greek Ἄννα (Ánna), from Biblical Hebrew חַנָּה (Ḥannâ).

Elsewhere

Serbo-Croatian