An older spelling of ancylostomiasis, the hookworm infection of the intestines that causes chronic blood loss and iron-deficiency anemia. The variant spelling reflects the Greek root ankylos, meaning bent or hooked, describing the worm’s curved shape, while modern parasitology favors the ancylostomiasis spelling. Both refer to the same disease: hookworm larvae penetrate the skin from contaminated soil, migrate through the lungs, and settle in the small intestine where adult worms attach and feed on blood. The clinical picture of weakness, pallor, and impaired growth is identical regardless of spelling. Medical dictionaries retain the older form as a cross-reference, a reminder that disease names evolve with the science, while patients in endemic regions need the same treatment, sanitation, and footwear whatever the textbook calls it.