anabranch

Anabranch \An"a*branch\, n. [Anastomosing + branch.]
   A branch of a river that re["e]nters, or anastomoses with,
   the main stream; also, less properly, a branch which loses
   itself in sandy soil. [Australia]
   [1913 Webster]

         Such branches of a river as after separation reunite, I
         would term anastomosing branches; or, if a word might
         be coined, anabranches, and the islands they form
         branch islands.                          --Col.
                                                  Jackson.
   [Webster 1913 Suppl.]
    

Billabong \Bil"la*bong`\, 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.]