LATIN DICTIONARYLexicon Latīnum
proper noun · masculinesecond declension

Petrōnius1

Petrōnius m sg (genitive Petrōniī or Petrōnī)
Classical[pɛˈtroː.ni.ʊs]Ecclesiastical[peˈtrɔː.ni.us]

Meaning

  1. a Roman nomen gentile, gens or "family name" famously held by
  2. Gaius Petronius Arbiter, a Roman courtier

Declension

declension
formsingularplural
nominativePetrōnius—
genitivePetrōniī
Petrōnī
—
dativePetrōniō—
accusativePetrōnium—
ablativePetrōniō—
vocativePetrōnī—

Pē^trōnĭus, i, m.,
I. name of a Roman gens.—So, esp.: Petronius Arbiter, a Roman knight, a favorite of the emperor Nero, perh. the same person with Petronius, the author of a Latin romance which is preserved in a fragmentary state, Tac. A. 16, 17 sq.—In fem.: Pē^trōnĭa, ae, the first wife of the emperor Vitellius, Tac. H. 2, 64; Suet. Vit. 6.—Hence,
A. Pē^trōnĭus, a, um, adj., of or belonging to a Petronius, Petronian: Petronia amnis est in Tiberim profluens, quam magistratus auspicato transeunt, cum in campo quid agere voluntquod genus auspicii peremne vocatur, Fest. p. 250 Müll.: Petronia lex, respecting slaves: post legem Petroniam et senatusconsulta ad eam legem pertinentia, dominis, potestas ablata est ad bestias depugnandas suo arbitrio servos tradere, Dig. 48, 8, 11, § 3; ib. 40, 1, 24.—
B. Pē^trōnĭānus, a, um, adj., of or belonging to a Petronius, Petronian: Petroniana Albucia, Fulg. Myth. praef. 1.

Origins

Disputed. Perhaps related to South Picene 𐌐𐌄𐌕𐌓𐌞𐌍𐌉𐌔 (petrúnis) and Umbrian 𐌐𐌄𐌕𐌓𐌖𐌍𐌉𐌀 (petrunia). According to Poultney, the term was perhaps borrowed from an Osco-Umbrian language, which itself formed the name from Proto-Italic *kʷetru-. Alternatively, a derivation from petrō (“a rustic, yokel”) has been suggested.

In the Academy Smith's classical dictionaries

adjectivefirst/second-declension adjective
Petrōnius2
Petrōnius (feminine Petrōnia, neuter Petrōnium)
Classical[pɛˈtroː.ni.ʊs]Ecclesiastical[peˈtrɔː.ni.us]

Meaning

  1. adjectiveof or pertaining to the gens Petronia

Declension

singular
formmasculinefeminineneuter
nominativePetrōniusPetrōniaPetrōnium
genitivePetrōniīPetrōniaePetrōniī
dativePetrōniōPetrōniaePetrōniō
accusativePetrōniumPetrōniamPetrōnium
ablativePetrōniōPetrōniāPetrōniō
vocativePetrōniePetrōniaPetrōnium
plural
formmasculinefeminineneuter
nominativePetrōniīPetrōniaePetrōnia
genitivePetrōniōrumPetrōniārumPetrōniōrum
dativePetrōniīsPetrōniīsPetrōniīs
accusativePetrōniōsPetrōniāsPetrōnia
ablativePetrōniīsPetrōniīsPetrōniīs
vocativePetrōniīPetrōniaePetrōnia

pē^trōnĭus, a, um, adj. 1. petra,
I. rock-, crag-, mountain- (very rare): canes, Grat. Cyneg. 202.

Origins

Disputed. Perhaps related to South Picene 𐌐𐌄𐌕𐌓𐌞𐌍𐌉𐌔 (petrúnis) and Umbrian 𐌐𐌄𐌕𐌓𐌖𐌍𐌉𐌀 (petrunia). According to Poultney, the term was perhaps borrowed from an Osco-Umbrian language, which itself formed the name from Proto-Italic *kʷetru-. Alternatively, a derivation from petrō (“a rustic, yokel”) has been suggested.

In the Academy Smith's classical dictionaries

Quick answers

What does Petrōnius mean in Latin?
Petrōnius, a proper noun, means “a Roman nomen gentile, gens or "family name" famously held by”.
What is the genitive of Petrōnius?
The genitive singular is Petrōniī. Petrōnius is masculine, second declension.
How do you pronounce Petrōnius?
In classical Latin, [pɛˈtroː.ni.ʊs]; in ecclesiastical (church) Latin, [peˈtrɔː.ni.us].