ACCIDENTAL means something of the nature of an accident, or that is not essential to its subject but indifferent thereto. See ACCIDENT and ESSENTIAL.

Thus, whiteness is accidental to marble, and heat to iron.

Accidental point, in perspective, is a point in the horizontal line where lines parallel to one another, though not perpendicular to the picture or representation, meet. See POINT, PERSPECTIVE, etc.

Accidental dignities and debilities, in astrology, are certain casual dispositions and assertions of the planets whereby they are supposed to be either strengthened or weakened by their being in such a house of the figure, etc.