What is "ternoise"

The river Ternoise (Dutch: Ternaas) is one of the small chalk streams that flow from the plateau of the southern Boulonnais and Picardy, via the Canche, into the English Channel. The basin of the Ternoise extends to and lies in the southern end of the département of Pas-de-Calais. It is one of the rivers of the Seven Valleys tourist area and gives its name to the Ternois area.