What does calendārium mean in Latin?

calendārium, a noun, means “an account book or debt book”.

What is the genitive of calendārium?

The genitive singular is calendāriī. calendārium is neuter, second declension.

In classical Latin, [ka.ɫɛnˈdaː.ri.ũː]; in ecclesiastical (church) Latin, [ka.lenˈdaː.ri.um].

noun · neutersecond declension

calendārium n (genitive calendāriī or calendārī)

Classical[ka.ɫɛnˈdaː.ri.ũː]Ecclesiastical[ka.lenˈdaː.ri.um]

declension
form	singular	plural
nominative	calendārium	calendāria kalendāria
genitive	calendāriī calendārī, kalendārī, kalendāriī	calendāriōrum kalendāriōrum
dative	calendāriō kalendāriō	calendāriīs kalendāriīs
accusative	calendārium	calendāria kalendāria
ablative	calendāriō kalendāriō	calendāriīs kalendāriīs
vocative	calendārium	calendāria kalendāria

călendārĭum, v. kalendarium.

From calendārius (“of the calends”), from calō (“to call out”). By surface analysis, calō + -ārium.

Elsewhere

Italo-Romance

Gallo-Romance

Insular Romance

Balkano-Romance