Etymology Cheese

The word cheese comes from Latin caseus, from which the modern word casein is closely derived. The earliest source is from the proto-Indo-European root *kwat-, which means "to ferment, become sour".
More recently, cheese comes from chese (in Middle English) 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 *kasjus, which in turn is an early borrowing from Latin.
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, Italian formaggio, Catalan formatge, Breton fourmaj, and Provençal furmo are derived. The word Cheese itself is occasionally employed in a sense that means "molded" or "formed". Head cheese uses the word in this sense.