ravaRaka
ravaṇaka , nt. , some kind of filtering vessel : °kam Mvy 9024 = Tib. bum tshags gceḥu can , filter-vessel provided with a pipe ; Chin. water-filter that has a tongue (spout) ; Jap. filter made of bamboo . Prob. = Pali ravaṇaghaṭa, to which the bladder is compared in Vism. 264.37, 362.36 , app. because ( 265.1 ff. ) no way of entrance (of the urine) into it is evident, while the way of exit is evident . This suggests that our words ( Pali and BHS ) designate a vessel of porous material (bamboo acc. to Jap. ) thru which water could be soaked in (and filtered), then to be poured out thru a spout.