Which is named after:
Terai (tuh-RAI) - n., belt of marshy land between the Himalaya foothills and the Ganges floodplain.
From Hindustani तराई (tarāī) or ترائی (tarāī), meaning wetland, from Persian تر (tar) / wet. More about the hat, which was first called that in 1888.
---L.