Kalmar "Infusoria" yawanci tana nufin rukuni na kwayoyin halittun ruwa, da farko protozoans, waɗanda ake samu a cikin ruwa mai tsabta da ruwan gishiri. Kalmar ta samo asali ne daga kalmar Latin "infundere," ma'ana zubawa ko sanyawa, wanda ke nuna hanyar gano wadannan kwayoyin halitta ta hanyar jiko kwayoyin halitta a cikin ruwa. Infusoria ya ƙunshi nau'ikan kwayoyin halitta masu sel guda ɗaya, irin su ciliates, flagellates, da amoebas, waɗanda ke taka muhimmiyar rawa a cikin halittun ruwa a matsayin masu amfani da kuma masu bazuwa.