Given two points x = (x 1, x 2, x 3), y = (y 1, y 2, y 3) their displacement is a vector y − − x = ( y 1 − − x 1 ) e 1 + ( y 2 − − x 2 ) e 2 + ( y 3 − − x 3 ) e 3 . which specifies the position of y relative to x. The length of this vector gives the straight-line distance from x to y. Displacement has the dimensions of length.