principal : Idioms & Phrases


Principal axes of a quadric

  • (Geom.), three lines in which the principal planes of the solid intersect two and two, as in an ellipsoid.
Webster 1913

Principal axis

  • noun a line that passes through the center of curvature of a lens so that light is neither reflected nor refracted
    optic axis.
    • in a normal eye the optic axis is the direction in which objects are seen most distinctly
WordNet
  • . See Axis of a curve, under Axis.
Webster 1913

Principal challenge

  • . (Law) See under Challenge.
Webster 1913

principal diagonal

  • noun the diagonal of a square matrix running from the upper left entry to the lower right entry
    main diagonal.
WordNet

principal investigator

  • noun the scientist in charge of an experiment or research project
    PI.
WordNet

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.
Webster 1913

Principal plane

  • . See Plane of projection (a), under Plane.
Webster 1913

Principal point

  • (Persp.), the projection of the point of sight upon the plane of projection.
Webster 1913

Principal ray

  • (Persp.), the line drawn through the point of sight perpendicular to the perspective plane.
Webster 1913

Principal section

  • (Crystallog.), a plane passing through the optical axis of a crystal.
Webster 1913

principal sum

  • noun capital as contrasted with the income derived from it
    corpus; principal.
WordNet

school principal

  • noun the educator who has executive authority for a school
    head; head teacher; principal.
    • she sent unruly pupils to see the principal
WordNet