Literally 'dis-ease' — Old French 'desaise' (lack of comfort), originally any discomfort, narrowed to illness by the 1300s.
A disorder of structure or function in a human, animal, or plant, especially one that produces specific symptoms.
From Old French 'desaise' (lack of ease, discomfort), formed from the prefix 'des-' (away, without) + 'aise' (ease, comfort). The word originally meant simply 'discomfort' or 'uneasiness' — it had no medical meaning at all. By the late fourteenth century it narrowed to mean specifically a bodily ailment, and the older general sense of 'discomfort' faded entirely. The word is a perfectly transparent compound: dis-ease, the absence of ease. Key roots: des- (Old French (from Latin
The word 'disease' originally had nothing to do with medicine — it meant any kind of discomfort or annoyance. You could be 'diseased' by a noisy neighbor or an uncomfortable chair. The medical sense only crystallized in the late 1300s, and the original meaning vanished so completely that modern speakers never suspect it existed.