LATIN DICTIONARYLexicon Latīnum
noun · masculinesecond declension

Cosacus

Cosacus m (genitive Cosacī, feminine Cosaca)

Meaning

  1. New LatinmasculineCossack
    Viduae Cosacorum uxores orbataque illorum proles, domus Cosaticae et uxores, eorum absentibus maritis, cum operi belli vel quibuscunque servitiis militaribus accincti fuerint, ne ad ulla ferenda plebi debita ac communia onera adigantur, extorsionibus tributariis aggraventur pactum sancitumque est.1710 April 5, Philippus Orlik, chapter XI, in Pacta et Constitutiones legum libertatumque Exercitus Zaporoviensis, Bender:
    7125–1617. finito, et 7126–1618 veniente, exit Skender pasca contra Cosacos in terram Lehicham, minorem Russiam, et tunc advenit Bethlen Gabro et Radul Bogdaniae et Alexander Valachiae, verum non multi ceciderunt, et nonnullae palancae duntaxat incensae sunt. Postremo venit etiam perfidus Tatarus Cantamir, et populatus est minorem Russiam et 53 millia hominum praeter peccora abduxit.In the ending year 7125–1617 and beginning 7126–1618 Skender leaves the meadows against the Cossacks into Lechic earth, Little Russia, and then comes Bethlen Gabro and Radul of Bogdania and Alexander of Wallachia, but some fell, and some palankas at least have been set on fire. Later comes also the perfidious Tatar Cantamir, and populates Little Russia and abducts 53 thousand humans apart from livestock.1797, Franjo Ksaver Pejačević, “Chronica Serbica Despotae Georgii Branković”, in Arkiv za povjestnicu jugoslavensku, volume III, Zagreb, published 1854, page 30:

Declension

declension
formsingularplural
nominativeCosacus
Cosaca, Cossaca
Cosacī
Cosacae, Cossacae, Cossacī
genitiveCosacī
Cosacae, Cossacae, Cossacī
Cosacōrum
Cosacārum, Cossacārum, Cossacōrum
dativeCosacō
Cosacae, Cossacae, Cossacō
Cosacīs
Cossacīs
accusativeCosacum
Cosacam, Cossacam, Cossacum
Cosacōs
Cosacās, Cossacās, Cossacōs
ablativeCosacō
Cosacā, Cossacā, Cossacō
Cosacīs
Cossacīs
vocativeCosace
Cosaca, Cossaca, Cossace
Cosacī
Cosacae, Cossacae, Cossacī

Origins

Through Polish, Serbo-Croatian or Hungarian according to the author, all three coming through Ukrainian from Old East Slavic козакъ (kozakŭ), itself from Old Turkic 𐰴𐰔𐰍𐰸 (qazǧag, “profiteer”).

Quick answers

What does Cosacus mean in Latin?
Cosacus, a noun, means “Cossack”.
What is the genitive of Cosacus?
The genitive singular is Cosacī. Cosacus is masculine, second declension.