The perspective formed by a ray incident on a surface and a perpendicular towards surface at point of incidence.
The angle that a straight range, ray of light, etc., meeting a surface, tends to make with a normal towards area at point of conference.
The position, often fixed, between the chord type of a-wing or horizontal stabilizer as well as the axis of the fuselage, calculated at root. In British called the perspective of assault.
the position which a ray of light, and/or line of occurrence of a body, dropping on any surface, tends to make with a perpendicular to this surface; in addition previously, the complement for this position.
the perspective that a line tends to make with a line perpendicular towards area at the point of occurrence