LATIN DICTIONARYLexicon Latīnum
proper noun · femininethird declension

Nēsis

Nēsis f sg (genitive Nēsidis)
Classical[ˈneː.sɪs]Ecclesiastical[ˈnɛː.s̬is]

Meaning

  1. A small island in the gulf of Naples, now Nisida
    Fuī enim apud illum multās hōrās in Nēside, cum paulō ante tuās litterās accēpisset.I spent several hours with him at Nesis, just after I received your letter.106 BCE – 43 BCE, Cicero, Epistulae ad Atticum 16.2.3.1
    Itaque quō celerius ēvāderem, prōtinus per altum ad Nēsida dērēxī praecīsūrus omnēs sinūs.So, in order to get away more quickly, I made straight out to sea for Nesis, with the purpose of cutting across all the inlets.c. 4 BCE – 65 CE, Seneca Minor, Epistulae Morales ad Lucilium 53.1.6

Declension

declension
formsingularplural
nominativeNēsis—
genitiveNēsidis—
dativeNēsidī—
accusativeNēsidem
Nēsida
—
ablativeNēside—
vocativeNēsis—

Nēsis, ĭdis (acc. ĭdem and ĭda), f., = Νησίς,
I. a small island in the bay of Naples, between Naples and Puteoli, now Nisita, Cic. Att. 16, 1, 1; 16, 4, 1; Sen. Ep. 51, 3; Stat. S. 3, 1, 148; Luc. 6, 90.

Origins

Borrowed from Ancient Greek Νησίς (Nēsís), from νησίς (nēsís, “islet”).

In the Academy Smith's classical dictionaries

Quick answers

What does Nēsis mean in Latin?
Nēsis, a proper noun, means “A small island in the gulf of Naples, now Nisida”.
What is the genitive of Nēsis?
The genitive singular is Nēsidis. Nēsis is feminine, third declension.
How do you pronounce Nēsis?
In classical Latin, [ˈneː.sɪs]; in ecclesiastical (church) Latin, [ˈnɛː.s̬is].