The Fennas word for river is abin. Abin is a last name. ABIN is an acronym for Agencia Brasileira de Inteligência (Brazilian Intelligence Agency). Abin Sur is a fictional superhero from the DC Comics Green Lantern.
How did I come up with this word? The word for river in Welsh is afon and river in Irish is abhainn. River in Breton seems to be ster or riniver, which is different from Welsh and Irish.