According to the late rGan Padma-rgyal-mtshan (from CIHTS, Sarnath), yul “place/field” or “object” is derived from yul ba “to go” (’gro ba) and that g.yul “battle”or “army” is derived from the causative form of yul ba. How plausible is this? One will have to examine. Cf. Jäschke 1881: s.v. yul ba “less correct spelling for nyul ba.” If we consider the meaning of yul yul as rgyug rgyug (brDa dkrol gser gyi me long, s.v. yul yul), the etymology seems justified.