Personal blog of Dorji Wangchuk alias Kuliśeśvara (Germany). It is for pure speculations and reflections.
December 29, 2011
According to the dGe chos gsung ’bum (vol. 5, p. 77), the etymology of rba klong (“wave”) is “protrusion/hill and depression/valley” (’bur dang lung). It is also spelt dba’ klong. See the Thon mi’i dgongs rgyan (p. 241).