ˌyu̇rəˈdinēəm noun
( plural uredin·ia -ēə)
Etymology: New Latin, from Latin uredin-, uredo blast, blight + New Latin -ium
: the crowded usually yellow or brownish aggregation of spore-bearing hyphae and urediospores of a rust forming pustules or sori that become exposed by rupture of the host's cuticle or epidermis beneath which they develop