What is the medical term for nail disease?

The correct answer, which refers to nail disease, is onychosis. This term is used as a broad designation for any disease or disorder affecting the nails, including changes in their appearance, structure, or function. Onychosis encompasses various conditions that can affect the nail bed, nail plate, and surrounding tissues.

Onycholysis specifically pertains to the separation of the nail from the nail bed, usually as a result of trauma, infection, or other underlying conditions. Onychomycosis is a term for a fungal nail infection leading to discoloration, thickening, or even destruction of the nail. Onychalgia describes pain related to the nails, which may be a symptom of a condition rather than a term for the disease itself. Hence, onychosis is the most comprehensive term for any nail disease, making it the appropriate choice in this context.