At all fetches under various wind velocities the wind-stress coefficient is related to the nondimensional fetch gL/U=z (g is the gravitational acceleration, L the fetch, and Uz the wind velocity measured at elevation z, which increases with both wind velocity and fetch). A unique relationship was found between the wave age and nondimensional fetch; the former can therefore be used as an alternate parameter for the latter, this is especially useful for the open sea.