ANIMALCULE

n. germ, microscopic organism

Animalcule ("little animal", from Latin animal + the diminutive suffix -culum) is an older term for a microscopic animal or protozoan. Some better-known animalcules include:Rotifers, called wheel animalculesParamecium, called slipper animalculesStentor, called trumpet animalculesVorticella, and other peritrichs, called bell animalculesActinophrys, and other heliozoa, called sun animalculesAmoeba, called proteus animalcules
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Noun
1. microscopic organism such as an amoeba or paramecium
(synonym) animalculum
(hypernym) organism, being

n. animalcule, germ

(n.)
An animal, invisible, or nearly so, to the naked eye. See Infusoria.
  

(n.)
A small animal, as a fly, spider, etc.