‖n.; pl. Haematozoa [ NL., fr. Gr. a"i^ma, a"i`matos, blood + zw^, on animal. ] (Zool.) A parasite inhabiting the blood; esp.: (a) Certain species of nematodes of the genus Filaria, sometimes found in the blood of man, the horse, the dog, etc. (b) The trematode, Bilharzia haematobia, which infests the inhabitants of Egypt and other parts of Africa, often causing death. [ 1913 Webster ]