The Collaborative International Dictionary of English v.0.48:
Sporangium \Spo*ran"gi*um\ (sp[-o]*r[a^]n"j[i^]*[u^]m), n.; pl. Sporangia (sp[-o]*r[a^]n"j[i^]*[.a]). [NL., fr. Gr. ? a sowing, seed + ? a receptacle.] (Bot.) A spore case in the cryptogamous plants, as in ferns, etc. [1913 Webster]WordNet (r) 3.0 (2006):
sporangium n 1: organ containing or producing spores [syn: sporangium, spore case, spore sac]