Pollotarianism is the practice of adhering to a diet that incorporates poultry as the only source of meat in an otherwise vegetarian diet. While "pollo" means chicken in Spanish and in Italian, pollotarians are known to incorporate different forms of poultry, like duck and turkey in their diet. Pollotarians may also eat dairy products. The term "pollo-vegetarian" was first used in nutritional textbooks in the 1980s to describe a semi-vegetarian diet that incorporates poultry. Historian Rod Preece describes pollotarians as "those who refrain from mammals but are willing to eat the flesh of birds notably chickens."