The doctors, lawyers and dentists in 1880 included in the professional service because they were the practitioners. The professional service occupies the occupants from arts and science that requires certification. They require skills and knowledge to perform work and come under the tertiary sector of the economy.
The occupational classification that included doctors, lawyers, and dentists in 1880 was the 'professional service' category. It would not be agriculture, fisheries, and mining because those professions are not in that field.
