The word cheese comes from Latin caseus, from which the modern word casein is also derived. The earliest source is from the proto-Indo-European root *kwat-, which means "to ferment, become sour". The word cheese comes from chese (in Middle Englich) and cīese or cēse (in Old English). Similar words are shared by other West Germanic languages-West Frisian tsiis, Dutch kaas, German Käse, Old High German chāsi- all from the reconstructed West-Germanic form *kāsi, which in turn is an early borrowing from Latin.
The Online Etymological Dictinary states that "cheese" comes from "Old English cyse (West Saxon), cese (Anglian)...from West Germanic *kasjus (source also of Old Saxon kasi, Old High German chāsi, German Käse, Middle Dutch case, Dutch kaas), from Latin caseus (for) "cheese" (Source of Italian cacio, Spanish queso, Irish caise, Welsh caws)."The Online Etymological Dictinary states that the word is of "unknown origin; perhaps from a PIE root *kwat-"to ferment, become sour" (source also of Prakrit chasi "buttermilk;" Old Church Slavonic kvasu "leaven; fermented drink," kyselu "sour,"-kyseti "to turn sour;" Czech kysati "to turn sour, rot;" Sanskrit kvathati "boils, seethes;" Gothic hwabjan "foam"). Also compare fromage. Old Norse ostr, Danish ost, Swedish ost are related Latin ius "broth, sauce, juice."
The Online Etymological Dictinary states that "cheese" comes from "Old English cyse (West Saxon), cese (Anglian)...from West Germanic *kasjus (source also of Old Saxon kasi, Old High German chāsi, German Käse, Middle Dutch case, Dutch kaas), from Latin caseus (for) "cheese" (Source of Italian cacio, Spanish queso, Irish caise, Welsh caws)."The Online Etymological Dictinary states that the word is of "unknown origin; perhaps from a PIE root *kwat-"to ferment, become sour" (source also of Prakrit chasi "buttermilk;" Old Church Slavonic kvasu "leaven; fermented drink," kyselu "sour,"-kyseti "to turn sour;" Czech kysati "to turn sour, rot;" Sanskrit kvathati "boils, seethes;" Gothic hwabjan "foam"). Also compare fromage. Old Norse ostr, Danish ost, Swedish ost are related Latin ius "broth, sauce, juice."
When the Romans began to make hard cheeses for their legionaries supplies, a new word started to be used: formaticum, from caseus formatus, or "molded cheese" (as in "formed", not "moldy"). It is from this word that the French fromage, standard Italian formaggio, Catalan formatge, Breton fourmaj, and Occitan fromatge (or formatge) are derived. Of the Romance languages, Spanish, Portuguese, Romanian, Tuscan and Southern Italian dialects use words derived from caseus (queso, gueijo, cas and caso for example). The word cheese itself is occasionally employed in a snse that means "molded" or "formed". Head Cheese uses the word in this sense. The term "cheese" is also used a a noun, verb and adjective in a number of figurative expressions. (e.g. "the big cheese", "to be cheesed off", and "cheesy lyrics").
source : https://en.wikipedia.org/wiki/Cheese
