The word rim gro does seem to have an etymology, but what could it be? The first syllable may (but need not) be derived from rim gyis “gradually, sequentially, in a series of subsequent steps” but what about gro? It cannot mean “wheat” here, can it? Or, could it be derived from ’gro ba “to go” (i.e. in the sense of “to go near, approach someone so as to pay respect, to tend to, and so on)? Any sources of inspiration out there?