Analysis of information sources in references of the Wikipedia article "Billabong" in English language version.
'Bill' = 'bile' = 'lip or mouth' and 'abong' is from 'abhainn' = 'river' with a parasitic 'G' added. A billabong probably has a mouth shape of sorts being at a bend in a river.
'Bill' = 'bile' = 'lip or mouth' and 'abong' is from 'abhainn' = 'river' with a parasitic 'G' added. A billabong probably has a mouth shape of sorts being at a bend in a river.