Rational normal scroll
In mathematics, a rational normal scroll is a ruled surface of degree n in projective space of dimension n + 1. Here "rational" means birational to projective space, "scroll" is an old term for ruled surface, and "normal" refers to projective normality (not normal schemes).
A non-degenerate irreducible surface of degree m – 1 in Pm is either a rational normal scroll or the Veronese surface.