caseus

Unknown according to De Vaan.^[1] The old hypothesis deriving it from Proto-Indo-European *kwath₂ (“to ferment, become sour”)^[2] has the problem that *w isn't supposed to disappear in Latin (the expected outcome would start with qua- and not ca-). In this case, the cognates listed under *kweth₂- are perhaps loans from the same substrate source as the Latin term.

Alternatively, taking into account Ossetian цыхт (cyxt) (<< Proto-Indo-European *(s)teyg- (“to be sharp; to sting”)), Proto-Indo-European *ḱes- (“to cut”) can be tentatively supposed as an ultimate source of the term; however, the vowel length mismatches.

• (Classical Latin) IPA^(key): [ˈkaː.se.ʊs]
• (modern Italianate Ecclesiastical) IPA^(key): [ˈkaː.s̬e.us]

cāseus m (genitive cāseī); second declension

1. cheese

   Synonyms: (medieval) fōrmāticum, fōrmāgium

   • 8 CE, Ovidius, Fasti 4.769:

     ‘ūbera plēna premam, referat mihi cāseus aera,
     dentque viam liquidō vīmina rāra serō.’

     ‘‘Let me squeeze full udders, may my cheese repay me with money,
     and may the wicker strainer give a passage to the liquid whey.’’
     (A shepherd’s prayer to Pales.)

Second-declension noun.

• “caseus”, in Charlton T. Lewis and Charles Short (1879), A Latin Dictionary, Oxford: Clarendon Press
• “caseus”, in Charlton T. Lewis (1891), An Elementary Latin Dictionary, New York: Harper & Brothers
• "caseus", in Charles du Fresne du Cange, Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
• “caseus”, in Gaffiot, Félix (1934), Dictionnaire illustré latin-français, Hachette.
• “caseus”, in Harry Thurston Peck, editor (1898), Harper’s Dictionary of Classical Antiquities, New York: Harper & Brothers
• Walther von Wartburg (1928–2002), “caseus”, in Französisches Etymologisches Wörterbuch (in German), volume 2: C Q K, pages –456-58