What does caseous mean?
Caseous is an adjective meaning cheeselike — describing something that has the color, texture, or crumbly consistency of cheese. Though it can be used literally for curdled dairy products, its dominant modern home is medicine. Pathologists use 'caseous' to characterize necrotic tissue that has died and taken on a pale, dry, crumbly appearance strikingly reminiscent of cottage cheese; 'caseous necrosis' is the classic description of tissue damage in tuberculosis and certain fungal infections. The word derives from the Latin caseus, meaning cheese — the same root that gives us casein, milk's principal protein, and, through Old English, the word cheese itself. Because of this technical flavor, caseous reads as formal or scientific rather than conversational; writers describing food would more naturally reach for cheeselike. It remains a precise, evocative term wherever an exact comparison to cheese is wanted.
Of, relating to, or resembling cheese; having a cheeselike texture or consistency.
"The curds had set into a firm, caseous layer across the top of the dish."
In non-technical writing, 'cheeselike' is the more natural choice.
(Medicine) Denoting necrotic tissue that is soft, dry, and crumbly like cheese, characteristic of tuberculosis.
"Histology showed caseous necrosis within the enlarged lymph node."
Almost always encountered in the phrase 'caseous necrosis.'
When doctors describe tuberculosis lesions as 'caseous,' they mean the dead tissue literally looks and crumbles like cottage cheese — a vivid image borrowed straight from Latin.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of caseous
Caseous comes from the Latin caseus, meaning cheese, adopted into English in the early modern period, likely via scientific Latin. The same Latin root produced casein, the name of the chief protein in milk, coined in the nineteenth century. Through Old English cīese, ultimately also descended from caseus, the root survives in the everyday word cheese; Romance languages preserve it directly in forms such as Spanish queso and Portuguese queijo.
How caseous is actually used
Formal and technical in register. Outside of medicine, microbiology, and food science, 'caseous' is rare; everyday contexts favor 'cheeselike' or 'cheesy.' In medical usage it appears most often in the fixed phrase 'caseous necrosis.'
Easily confused with caseous
Despite their similar spellings, 'caseous' means cheeselike in texture, while 'gaseous' means relating to or existing as gas.