A vector is any quantity that has magnitude and direction. A scalar is any quantity that has magnitude but no direction. Displacement and velocity are vectors, whereas distance and speed are scalars. ...A vector is any quantity that has magnitude and direction. A scalar is any quantity that has magnitude but no direction. Displacement and velocity are vectors, whereas distance and speed are scalars. In one-dimensional motion, direction is specified by a plus or minus sign to signify left or right, up or down, and the like.