Vocative singular is fili
Vocative plural is filii
The vocative is the same as the nominative, but when a noun ends in "ius", that piece is replaced with "i". The vocative plural remains the same as the nominative plural.
Singularnominative/vocative: filiagenitive: filiaedative: filiaeaccusative: filiamablative: filiaPluralnominative/vocative: filiaegenitive: filiarumdative: filiabusaccusative: filiasablative: filiabusThe forms of the dative and ablative plural end in -abus,rather than the usual -is, in order to distinguish them for the corresponding cases of the word filius.
filius
Filium is the objective case of the Latin word filius which means "son".
Filius.
Meus filius
Filius
filius
Accusative singular of 'filius,' meaning 'son.'
Filius oblitus.
filius est
Nullius Filius
Both mean son of the sea. Preferred word order is Filius maris.