# Principal axis

Principal axis
Principal Prin"ci*pal, a. [F., from L. principalis. See {Prince}.] 1. Highest in rank, authority, character, importance, or degree; most considerable or important; chief; main; as, the principal officers of a Government; the principal men of a state; the principal productions of a country; the principal arguments in a case. [1913 Webster]

Wisdom is the principal thing. --Prov. iv. 7. [1913 Webster]

2. Of or pertaining to a prince; princely. [A Latinism] [Obs.] --Spenser. [1913 Webster]

{Principal axis}. See {Axis of a curve}, under {Axis}.

{Principal axes of a quadric} (Geom.), three lines in which the principal planes of the solid intersect two and two, as in an ellipsoid.

{Principal challenge}. (Law) See under {Challenge}.

{Principal plane}. See {Plane of projection} (a), under {Plane}.

{Principal of a quadric} (Geom.), three planes each of which is at right angles to the other two, and bisects all chords of the quadric perpendicular to the plane, as in an ellipsoid.

{Principal point} (Persp.), the projection of the point of sight upon the plane of projection.

{Principal ray} (Persp.), the line drawn through the point of sight perpendicular to the perspective plane.

{Principal section} (Crystallog.), a plane passing through the optical axis of a crystal. [1913 Webster]

The Collaborative International Dictionary of English. 2000.

### Look at other dictionaries:

• principal axis — Axis Ax is, n.; pl. {Axes}. [L. axis axis, axle. See {Axle}.] A straight line, real or imaginary, passing through a body, on which it revolves, or may be supposed to revolve; a line passing through a body or system around which the parts are… …   The Collaborative International Dictionary of English

• principal axis — i. The lateral, vertical, and longitudinal axes. ii. The axis of relative wind. iii. The principal inertial axis: that line passing through the center of gravity in a plane of symmetry about which a long, slender body tends to rotate when rolling …   Aviation dictionary

• principal axis — pagrindinė ašis statusas T sritis automatika atitikmenys: angl. principal axis vok. Hauptachse, f rus. главная ось, f pranc. axe principal, m …   Automatikos terminų žodynas

• principal axis — pagrindinė ašis statusas T sritis fizika atitikmenys: angl. principal axis vok. Hauptachse, f rus. главная ось, f pranc. axe principal, m …   Fizikos terminų žodynas

• Principal Axis Tree — L’arbre d axes principaux (en anglais : Principal Axis Tree), souvent abrégé PAT est un algorithme permettant de diviser un espace de points de manière efficiente en vue de résoudre rapidement le problème des plus proches voisins. Elle fut… …   Wikipédia en Français

• Principal axis tree — L’arbre d axes principaux (en anglais : Principal Axis Tree), souvent abrégé PAT est un algorithme permettant de diviser un espace de points de manière efficiente en vue de résoudre rapidement le problème des plus proches voisins. Elle fut… …   Wikipédia en Français

• Principal axis theorem — In the mathematical fields of geometry and linear algebra, a principal axis is a certain line in a Euclidean space associated to an ellipsoid or hyperboloid, generalizing the major and minor axes of an ellipse. The principal axis theorem states… …   Wikipedia

• principal axis — noun a line that passes through the center of curvature of a lens so that light is neither reflected nor refracted in a normal eye the optic axis is the direction in which objects are seen most distinctly • Syn: ↑optic axis • Hypernyms: ↑axis …   Useful english dictionary

• principal axis — main axis, chief axis …   English contemporary dictionary

• principal axis — prin·ci·pal axis prin(t) sə pəl n the line with respect to which a spherical mirror or lens system is symmetrical and which passes through both the center of the surfaces and their centers of curvature * * * optic a …   Medical dictionary