Sinuosity
ratio of the curvilinear length (along the curve) and the Euclidean distance (straight line) between end points of a curve
en-US/ˌsɪnjʊˈɑsɪti/
en-GB/ˌsɪnjʊˈɒsɪtɪ/
ratio of the curvilinear length (along the curve) and the Euclidean distance (straight line) between end points of a curve