Vector which is perpendicular to said surface or manifold. In a inner product space, the inner product of the normal vector with all vectors which comprise the surface is 0.
... bandleader (+ 1957)
March 1 - Glenn Miller, bandleader (+ 1944)
March 2 - Dr. Seuss, author (+ 1991)
March 8 - Victor de Kowa[?], actor (+ 1973)
March 6 - Josep ...