曲率弦

Curvature \Cur"va*ture\ (k?r"v?-t?r; 135), n. [L. curvatura. See
{Curvate}.]
1. The act of curving, or the state of being bent or curved;
a curving or bending, normal or abnormal, as of a line or
surface from a rectilinear direction; a bend; a curve.
--Cowper.

The elegant curvature of their fronds. --Darwin.

2. (Math.) The amount of degree of bending of a mathematical
curve, or the tendency at any point to depart from a
tangent drawn to the curve at that point.

{Aberrancy of curvature} (Geom.), the deviation of a curve
from a circular form.

{Absolute curvature}. See under {Absolute}.

{Angle of curvature} (Geom.), one that expresses the amount
of curvature of a curve.

{Chord of curvature}. See under {Chord}.

{Circle of curvature}. See {Osculating circle of a curve},
under {Circle}.

{Curvature of the spine} (Med.), an abnormal curving of the
spine, especially in a lateral direction.

{Radius of curvature}, the radius of the circle of curvature,
or osculatory circle, at any point of a curve.


Chord \Chord\ (k[^o]rd), n. [L chorda a gut, a string made of a
gut, Gr. chordh`. In the sense of a string or small rope, in
general, it is written cord. See {Cord}.]
1. The string of a musical instrument. --Milton.

2. (Mus.) A combination of tones simultaneously performed,
producing more or less perfect harmony, as, the common
chord.

3. (Geom.) A right line uniting the extremities of the arc of
a circle or curve.

4. (Anat.) A cord. See {Cord}, n., 4.

5. (Engin.) The upper or lower part of a truss, usually
horizontal, resisting compression or tension. --Waddell.

{Accidental, Common, & Vocal} {chords}. See under
{Accidental}, {Common}, and {Vocal}.

{Chord of an arch}. See Illust. of {Arch}.

{Chord of curvature}, a chord drawn from any point of a
curve, in the circle of curvature for that point.

{Scale of chords}. See {Scale}.