In the ninth edition of "Human Parasitology", published by People's Medical Publishing House. Mentioned in Chapter 2. (This is a medical textbook)

Parasitism, two organisms living side by side, a relationship in which one party benefits and the other suffers is called parasitism. The party that benefits is called a parasite, and if the parasite is an animal, it is called a parasite. The victimized party is called the host.

For example, roundworms that parasitize the human small intestine use food from the host’s digestive tract as their source of nutrition, and can also cause malnutrition and developmental disorders.