What does entozoa mean?
Entozoa refers to parasitic animals that live within the bodies of other creatures, most commonly parasitic worms—tapeworms, roundworms, flukes—settled in the intestines or other internal organs. The word is a Latinized plural whose singular is entozoon, and it derives from Greek roots meaning 'animals within.' Once a standard collective category in nineteenth-century zoological and medical writing, when naturalists divided parasites into internal (entozoa) and external (ectozoa) inhabitants, the term has largely fallen out of everyday scientific use; contemporary biologists prefer 'endoparasites' or simply name the specific organism involved. Encountering entozoa today usually signals historical, veterinary, or antiquarian prose. Its connotations are clinical rather than emotional, though the image of creatures dwelling inside a host carries an inherent unease. The related adjective entozoic describes something relating to or characteristic of these internal parasites.
nounEntozoa are animals that live as parasites inside the bodies of other animals, especially parasitic worms such as tapeworms and roundworms inhabiting the intestines. The term is used chiefly as a collective plural in older zoological classification.
- Parasitic animals living inside the body of a host animal, especially internal parasitic worms; used as a collective plural term in older zoology.
"The veterinarian explained that the calf's poor condition was caused by an infestation of entozoa in its digestive tract."
"Nineteenth-century medical texts devoted entire chapters to the entozoa found in human hosts."
"The sheep's chronic wasting was traced to entozoa lodged in the small intestine."
Entozoa is already plural; use the rare singular 'entozoon' for one individual parasite. Modern English sometimes treats 'entozoa' informally as a mass noun, but careful usage keeps it plural.
"A single entozoon can produce thousands of eggs within its host."
Before germ theory reshaped medicine, Victorian naturalists sorted every parasite into two tidy camps: entozoa living inside you, and ectozoa living on you.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of entozoa
The word entozoa comes from New Latin, combining the Greek 'entos' (within) with 'zōion' (animal), literally 'animals within.' It entered English scientific vocabulary in the early nineteenth century as part of the classificatory scheme that paired it with ectozoa for external parasites. It shares its Greek root with zoological terms such as zoology, protozoa, and spermatozoa.
Related word forms
How entozoa is actually used
A formal, technical, and somewhat dated term; modern parasitology more often speaks of endoparasites or names specific organisms. It functions as a Latinized plural (singular 'entozoon'), so verbs should agree plurally.
Easily confused with entozoa
Ectozoa are parasites that live on the outside of the host's body (such as lice and ticks), whereas entozoa live inside it.