What does Iūverna mean in Latin?

Iūverna, a proper noun, means “synonym of Hibernia: Ireland (an island and country in Western Europe)”.

What is the genitive of Iūverna?

The genitive singular is Iūvernae. Iūverna is feminine, first declension.

In classical Latin, [i.uːˈwɛr.na]; in ecclesiastical (church) Latin, [i.uˈvɛr.na].

proper noun · femininefirst declension

Iūverna f sg (genitive Iūvernae)

Classical[i.uːˈwɛr.na]Ecclesiastical[i.uˈvɛr.na]

historicalraresynonym of Hibernia: Ireland (an island and country in Western Europe)
Super Britanniam Iuverna est paene par spatioc. 45 CE, Pomponius Mela, De Chorographia 3.53.1
litora Iuvernae promovimus et modo captasc. 100 CE – c. 130 CE, Juvenalis, Saturae 2.160

Jūverna or Jūberna, ae, f.,

I. Ireland, Mela, 3, 6, 6; Juv. 2, 160.

Variant of the name Hī̆bernia, Iverna (Greek Ἰ̄έρνη (Īérnē), Ἰ̄ουερνία (Īouernía)) etc.