Which term refers to a medical condition related to the skin?

Dermatology is the correct term that refers to the medical field concerned with the diagnosis and treatment of skin conditions. This specialty encompasses a wide range of issues, including rashes, skin infections, and various forms of skin cancer. It involves understanding both the structural and functional aspects of the skin and provides treatment options ranging from pharmacological therapies to surgical procedures.

The other terms represent different medical specialties: nephrology is related to the study and treatment of kidney conditions, cytology focuses on the study of cells, and cardiology pertains to heart-related diseases and conditions. Each of these fields addresses specific organ systems and does not pertain to the skin.