infusorian

noun

in·​fu·​so·​ri·​an ˈin-fyü-ˈzȯr-ē-ən  -ˈsȯr- 

: any of a heterogeneous group of minute organisms found especially in water with decomposing organic matter

especially : a ciliated protozoan

infusorian adjective

Word History

Etymology

New Latin Infusoria "group of minute organisms found in infusions of decaying matter" (by ellipsis from animalcula infusoria "animalcules found in infusions"), neuter plural of infūsōrius "pertaining to an infusion" (going back to Medieval Latin, "serving as a funnel," adjective derivative from the base of Latin infundere, past participle infūsus "to pour in, instill") + -an entry 1 — more at infuse

Note: The phrase animalcula infusoria was apparently introduced by the German anatomist Heinrich August Wrisberg (1739-1808) in Observationum de animalculis infusoriis satura (Göttingen, 1765), as a latinization of German Infusionsthierchen, used by the jurist and naturalist Martin Frobenius Ledermüller (1719-69) in Mikroskopischer Gemüths- und Augen-Ergötzung, Erstes Fünfzig (Nuremberg, 1760), p. 88. A Linnaean classification of Infusoria into genera and species was first attempted by the Danish naturalist Otto Friedrich Müller (1730-84) in Vermium terrestrium et fluvatilium, seu animalium infusoriorum, helminthicorum et testaceorum … succincta historia (Copenhagen & Leipzig, 1773-74).

First Known Use

1859, in the meaning defined above

Medical Definition

infusorian

noun

in·​fu·​so·​ri·​an -ē-ən 

: any of a heterogeneous group of minute organisms found especially in water with decomposing organic matter

especially : a ciliated protozoan

infusorian adjective