Principal plane
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 plane — n either of the two planes perpendicular to the principal axis and passing through one of the two principal points of an optical system * * * in radiology, the plane which contains the central ray of a radiation beam …   Medical dictionary

  • principal plane — pagrindinė plokštuma statusas T sritis fizika atitikmenys: angl. principal plane vok. Hauptebene, f rus. главная плоскость, f pranc. plan principal, m …   Fizikos terminų žodynas

  • principal plane — pagrindinė plokštuma statusas T sritis Gynyba apibrėžtis Fotogrametrijoje – vertikali plokštuma, kurioje yra pagrindinis įžambiosios nuotraukos taškas, lęšio (fotoaparato) perspektyvinis centras ir antžeminis nadyras. atitikmenys: angl. principal …   NATO terminų aiškinamasis žodynas

  • principal plane — A vertical plane that contains the principal point of an oblique photograph, the perspective center of the lens, and the ground nadir. It is the vertical plane containing the optical axis …   Aviation dictionary

  • principal plane — A vertical plane which contains the principal point of an oblique photograph, the perspective center of the lens, and the ground nadir …   Military dictionary

  • principal plane — noun : any of the planes perpendicular to the axis and passing through the principal points of an optical system * * * Optics. a plane that is perpendicular to the axis of a lens, mirror, or other optical system and at which rays diverging from a …   Useful english dictionary

  • principal plane — Optics. a plane that is perpendicular to the axis of a lens, mirror, or other optical system and at which rays diverging from a focal point are deviated parallel to the axis or at which rays parallel to the axis are deviated to converge to a… …   Universalium

  • principal plane of symmetry — a plane of symmetry in a crystal that includes two or more axes of symmetry …   Useful english dictionary

  • 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… …   The Collaborative International Dictionary of English

  • Principal axes of a quadric — 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… …   The Collaborative International Dictionary of English

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