Grb is a see also of lrn.

As a symbol grb

is the for grebo .

As a noun lrn is

(star) l'uminous '''r'''ed ' n ova — an astronomical event, believed to be a type of stellar explosion, intermediate in power between that of a nova and a supernova, which as the explosive debris expands it reddens and cools, opposite of novae and supernovae, in which thinning explosive debris exposes hotter interior layers.