Which prefix denotes 'painful' in medical terminology?

The prefix that denotes 'painful' in medical terminology is 'dys-.' This prefix is used to describe difficult or painful conditions. It is often associated with disorders or symptoms that indicate suffering or abnormality. For example, in the term 'dysmenorrhea,' 'dys-' signifies painful menstruation.

The other prefixes provided do not relate to pain. 'Litho-' refers to stones or calcifications, commonly used in terms like 'lithotripsy,' which involves breaking down stones. 'Chole-' pertains to bile or gall, as seen in 'cholecystitis,' which refers to inflammation of the gallbladder. 'Macro-' indicates something large or excessive, often seen in words like 'macrocytic,' which relates to larger than normal cells. Thus, 'dys-' is specifically focused on indicating a painful or difficult condition, making it the appropriate choice in this context.