Word Study
billabong
CIDE DICTIONARY
billabong, n. [Native name.].
In Australia, a blind channel leading out from a river; -- sometimes called an anabranch . This is the sense of the word as used in the Public Works Department; but the term has also been locally applied to mere back-waters forming stagnant pools and to certain water channels arising from a source. [Webster 1913 Suppl.]
OXFORD DICTIONARY
billabong, n. Austral. a branch of a river forming a backwater or a stagnant pool.
Etymology
Aboriginal Billibang Bell River f. billa water
For further exploring for "billabong" in Webster Dictionary Online