aecidium

Etymology
From, the diminutive form of. However Merriam-Webster takes the origin from and refers to the botanist John Hill, in his A General Natural History, or New and Accurate Descriptions of the Animals, Vegetables, and Minerals, of the Different Parts of the World, vol. II, A History of Plants (London: Printed for Thomas Osborne, 1751), p. 64: "We have called this genus, distinguished by its peculiar cells, Æcidium, from the Greek οικιδιον, cellula."

Noun

 * 1) The cupulate fruiting body borne upon the mycelium of certain fungi commonly parasitic upon specimens of the, , , and  families
 * 2)  A member of the form genus.

Translations

 * Portuguese: ecídio