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.
... Leonard Cohen
1992 Ian and Sylvia[?]
1993 Anne Murray
1994 Rush
1995 Buffy Sainte-Marie[?]
1996 David Clayton-Thomas[?]
1996 Denny Doherty[?]
1996 John ...