Correctly spelled; written with the proper letters.

Pertaining to the spelling of words; as, to make an orthographical mistake. Orthographic projection of the sphere, a delineation of the sphere upon a plane that cuts it in the middle, the eye being supposed to be placed at an infinite distance from it. A projection in which the eye is supposed to be at an infinite distance; so called because the perpendiculars from any point of the sphere will all fall in the common intersection of the sphere with the plane of the projection.