There are far more than two, and according to [1] it is indeed related via the proto-Germanic "ahwō" for stream or river. [1]: https://nl.wikipedia.org/wiki/Aa

There are far more than two, and according to [1] it is indeed related via the proto-Germanic "ahwō" for stream or river. [1]: https://nl.wikipedia.org/wiki/Aa_(waternaam) https://nl.wikipedia.org/wiki/Aa_(waternaam)