What does Basilus mean in Latin?

Basilus, a proper noun, means “a Roman nomen gentile, gens or "family name"”.

What is the genitive of Basilus?

The genitive singular is Basilī. Basilus is masculine, second declension.

In classical Latin, [ˈba.sɪ.ɫʊs]; in ecclesiastical (church) Latin, [ˈbaː.s̬i.lus].

proper noun · masculinesecond declension

Basilus m (genitive Basilī)

Classical[ˈba.sɪ.ɫʊs]Ecclesiastical[ˈbaː.s̬i.lus]

masculinea Roman nomen gentile, gens or "family name"
Ipse, cum maturescere frumenta inciperent, ad bellum Ambiorigis profectus per Arduennam silvam, quae est totius Galliae maxima atque ab ripis Rheni finibusque Treverorum ad Nervios pertinet milibusque amplius quingentis in longitudinem patet, Lucium Minucium Basilum cum omni equitatu praemittit, si quid celeritate itineris atque opportunitate temporis proficere possit;He himself, when the corn began to ripen, having set forth for the war with Ambiorix (through the forest Arduenna, which is the largest of all Gaul, and reaches from the banks of the Rhine and the frontiers of the Treviri to those of the Nervii, and extends over more than 500 miles), he sends forward L. Minucius Basilus with all the cavalry, to try if he might gain any advantage by rapid marches and the advantage of time.c. 52 BCE, Julius Caesar, Commentarii de bello Gallico 6.29