A microscopic or small organism, including an amoeba or paramecium, frequently regarded as being an animal.
Archaic a little animal, like a mosquito.
A minute or microscopic pet or protozoan.
A tiny animal, as a mouse or insect (fly, mosquito, midge).
a tiny animal, as a fly, spider, etc.
An animal, hidden, or nearly so, to your naked-eye. See Infusoria.
Any little pet, as a mouse, pest, etc.
a moment or microscopic pet, almost or quite hidden towards the naked eye, as an infusorian or rotifer; an animalculum: because, the bell-animalcule, a ciliate infusorian of this family Vorticellidæ; wheel-animalcule, a rotifer; bear-animalcule, a minute arachnidan of the order Arctisca. See slices under Arctisca, Rotifera, and Vorticella.