noun
- any of a former large group (Infusoria) of microscopic animals found in infusions of decayed organic matter and in stagnant water
- any of a former class (Infusoria) of protozoans found in most water, characterized by cilia which permit free movement, as paramecia or stentors
Origin:
< ModL (animalcula infusoria), neut. pl. of infusorius, pertaining to infusions (< L infusus: see infuse) + -an