1) Plant part 2) Plant structure 
A pycnidium (plural pycnidia) is an asexual fruiting body produced by mitosporic fungi in the form order Sphaeropsidales (Deuteromycota, Coelomycetes). It is often spherical or inversely pearshaped (obpyriform) and its internal cavity is lined with conidiophores. When ripe, an opening generally appears at the top, through which the pycnidiospores ...
A closed sporocarp, usually opening by a pore, that contains a cavity bearing conidia. (Pl. pycnidia.) 
• (n.) In certain fungi, a flask-shaped cavity from the surface of the inner walls of which spores are produced.
<plant biology> The male producing body of a rust. ... (09 Oct 1997) ... 
An asexual, spherical or flask-shaped fruiting body lined inside with conidiophores and producing conidia.
Pyc·nid'i·um noun ; plural Pycnidia . [ New Latin , from Greek ... crowded.] (Botany) In certain fungi, a flask-shaped cavity from the surface of the inner walls of which spores are produced. 
[n] - flask-shaped asexual structure containing conidia
noun flask-shaped asexual structure containing conidia
(in certain ascomycetes and fungi imperfecti) a globose or flask-shaped fruiting body bearing conidia on conidiophores.