Definition of "Waiau"

A river in western Southland, New Zealand, which flows into Te Waewae Bay.  examples

A river in north Canterbury, New Zealand, which flows into the Pacific Ocean, known since 2018 as the Waiau Uwha River.  examples

A river in Hawke's Bay, New Zealand, which joins the Wairoa River.  examples

A small town in north Canterbury, New Zealand, situated on the Waiau Uwha River.  examples