'Sorus' definitions:

Definition of 'sorus'

From: WordNet
noun
A spore-producing structure in certain lichens and fungi
noun
Cluster of sporangia usually on underside of a fern frond

Definition of 'Sorus'

From: GCIDE
  • Sorus \So"rus\, n.; pl. Sori. [NL., fr. Gr. ? a heap.]
  • 1. (Bot.) One of the fruit dots, or small clusters of sporangia, on the back of the fronds of ferns. [1913 Webster]
  • 2. (a) In parasitic fungi, any mass of spores bursting through the epidermis of a host plant. (b) In lichens, a heap of soredia on the thallus. [Webster 1913 Suppl.]