Disease vs. Diasease: Correct Spelling & Definition

"Diasease" is a misspelling. The correct term is "disease."

Disease (noun): A pathological condition of a part, organ, or system of an organism resulting from various causes (infection, genetic defect, environmental stress, lifestyle) and characterized by an identifiable group of signs, symptoms, or both. It impairs normal functioning and is typically associated with distinct structural/functional changes.

Etymology: Middle English disese "discomfort, distress," from Old French desaise "lack of ease" (des- "without" + aise "ease").