e/Degenerate conic

Information
has gloss	eng: In mathematics, a degenerate conic is a conic (degree-2 plane curve, the zeros of a degree-2 polynomial equation, a quadratic) that fails to be an irreducible curve. This can happen in two ways: either it is a reducible variety, meaning that its defining quadratic factors as the product of two linear polynomials (degree 1), or the polynomial is irreducible but does not define a curve, but instead a lower-dimension variety (a point or the empty set); this latter can only occur over a field that is not algebraically closed, such as the real numbers.
lexicalization	eng: degenerate conic
instance of	(noun) (geometry) a curve generated by the intersection of a plane and a circular cone conic, conic section