What does altellus mean in Latin?

altellus, a noun, means “an epithet or perhaps cognomen of Romulus”.

What is the genitive of altellus?

The genitive singular is altellī. altellus is masculine, second declension.

In classical Latin, [aɫˈtɛl.lʊs]; in ecclesiastical (church) Latin, [alˈtɛl.lus].

noun · masculinesecond declension

altellus m (genitive altellī)

Classical[aɫˈtɛl.lʊs]Ecclesiastical[alˈtɛl.lus]

masculinean epithet or perhaps cognomen of Romulus
Altellus Rōmulus dīcēbātur, quasi altus in tellūre, vel quod tellūrem suam aleret; sīve quod alerētur tēlīs; vel quod ā Tatiō Sabīnōrum rēge postulātus sit in colloquiō pācis, et alternīs vicibus audierit locūtusque fuerit. Sīcut enim fit dīminūtīve ā macrō macellus, a vafrō vafellus, ita ab alternō altellus.Altellus was Romulus called, as if 'high in the land', or because he nourished his land; or because he was nourished by weapons; or because he was summoned by Tatius for peace talks, and he listened and spoke by turns [alternīs vicibus]. For in the same way the diminutive macellus is derived from macer and vafellus from vafer, so altellus from alternus.1839 [8th century CE], Paulus Diaconus, edited by Karl Otfried Müller, Excerpta ex libris Pompeii Festi De significatione verborum, page 7, line 10:

Altellus, i, m.,

I. a surname of Romulus, Paul. ex Fest. p. 7 Müll.

See the quotation.