pəˈridēəm noun
( plural perid·ia -ēə ; also peridiums )
Etymology: New Latin, from Greek pēridion small leather bag, diminutive of pēra leather bag, wallet
: the outer envelope of the sporophore of many fungi: as
a. : the tough often two-layered cortical investment of the gleba of a gasteromycete
b. : the layer of sterile hyphae that surrounds an aecium of a rust fungus