What is "polar coordinates"

Polar \Po"lar\, a. [Cf. F. polaire. See Pole of the earth.]

1. Of or pertaining to one of the poles of the earth, or of a sphere; situated near, or proceeding from, one of the poles; as, polar regions; polar seas; polar winds.

2. Of or pertaining to the magnetic pole, or to the point to which the magnetic needle is directed.

3. (Geom.) Pertaining to, reckoned from, or having a common radiating point; as, polar co["o]rdinates.

   Polar axis, that axis of an astronomical instrument, as an equatorial, which is parallel to the earths axis.

   Polar bear (Zo["o]l.), a large bear ( Ursus maritimus syn. Thalarctos maritimus) inhabiting the arctic regions. It sometimes measures nearly nine feet in length and weighs 1,600 pounds. It is partially amphibious, very powerful, and the most carnivorous of all the bears. The fur is white, tinged with yellow. Called also White bear. See Bear.

   Polar body, Polar cell, or Polar globule (Biol.), a minute cell which separates by karyokinesis from the ovum during its maturation. In the maturation of ordinary ova two polar bodies are formed, but in parthogenetic ova only one. The first polar body formed is usually larger than the second one, and often divides into two after its separation from the ovum. Each of the polar bodies removes maternal chromatin from the ovum to make room for the chromatin of the fertilizing spermatozo["o]n; but their functions are not fully understood.

   Polar circles (Astron. & Geog.), two circles, each at a distance from a pole of the earth equal to the obliquity of the ecliptic, or about 23[deg] 28', the northern called the arctic circle, and the southern the antarctic circle.

   Polar clock, a tube, containing a polarizing apparatus, turning on an axis parallel to that of the earth, and indicating the hour of the day on an hour circle, by being turned toward the plane of maximum polarization of the light of the sky, which is always 90[deg] from the sun.

   Polar co["o]rdinates. See under 3d Co["o]rdinate.

   Polar dial, a dial whose plane is parallel to a great circle passing through the poles of the earth.
   --Math. Dict.

   Polar distance, the angular distance of any point on a sphere from one of its poles, particularly of a heavenly body from the north pole of the heavens.

   Polar equation of a line or Polar equation of a surface, an equation which expresses the relation between the polar co["o]rdinates of every point of the line or surface.

   Polar forces (Physics), forces that are developed and act in pairs, with opposite tendencies or properties in the two elements, as magnetism, electricity, etc.

   Polar hare (Zo["o]l.), a large hare of Arctic America ( Lepus arcticus), which turns pure white in winter. It is probably a variety of the common European hare ( Lepus timidus).

   Polar lights, the aurora borealis or australis.

   Polar opposition, or Polaric opposition or Polar contrast or Polaric contrast (Logic), an opposition or contrast made by the existence of two opposite conceptions which are the extremes in a species, as white and black in colors; hence, as great an opposition or contrast as possible.

   Polar projection. See under Projection.

   Polar spherical triangle (Spherics), a spherical triangle whose three angular points are poles of the sides of a given triangle. See 4th Pole, 2.

   Polar whale (Zo["o]l.), the right whale, or bowhead. See Whale.

Coordinate \Co*["o]r"di*nate\, n.

1. A thing of the same rank with another thing; one two or more persons or things of equal rank, authority, or importance.

   It has neither co["o]rdinate nor analogon; it is absolutely one.
   --Coleridge.

2. pl. (Math.) Lines, or other elements of reference, by means of which the position of any point, as of a curve, is defined with respect to certain fixed lines, or planes, called co["o]rdinate axes and co["o]rdinate planes. See Abscissa. Note: Co["o]rdinates are of several kinds, consisting in some of the different cases, of the following elements, namely:

   1. (Geom. of Two Dimensions) The abscissa and ordinate of any point, taken together; as the abscissa PY and ordinate PX of the point P (Fig. 2, referred to the co["o]rdinate axes AY and AX.

   2. Any radius vector PA (Fig. 1), together with its angle of inclination to a fixed line, APX, by which any point A in the same plane is referred to that fixed line, and a fixed point in it, called the pole, P.

   3. (Geom. of Three Dimensions) Any three lines, or distances, PB, PC, PD (Fig. 3), taken parallel to three co["o]rdinate axes, AX, AY, AZ, and measured from the corresponding co["o]rdinate fixed planes, YAZ, XAZ, XAY, to any point in space, P, whose position is thereby determined with respect to these planes and axes.

   4. A radius vector, the angle which it makes with a fixed plane, and the angle which its projection on the plane makes with a fixed line line in the plane, by which means any point in space at the free extremity of the radius vector is referred to that fixed plane and fixed line, and a fixed point in that line, the pole of the radius vector. Cartesian co["o]rdinates. See under Cartesian. Geographical co["o]rdinates, the latitude and longitude of a place, by which its relative situation on the globe is known. The height of the above the sea level constitutes a third co["o]rdinate. Polar co["o]rdinates, co["o]rdinates made up of a radius vector and its angle of inclination to another line, or a line and plane; as those defined in (b) and (d) above. Rectangular co["o]rdinates, co["o]rdinates the axes of which intersect at right angles. Rectilinear co["o]rdinates, co["o]rdinates made up of right lines. Those defined in

      1. and (c) above are called also Cartesian co["o]rdinates.

         Trigonometrical co["o]rdinates or Spherical co["o]rdinates, elements of reference, by means of which the position of a point on the surface of a sphere may be determined with respect to two great circles of the sphere.

         Trilinear co["o]rdinates, co["o]rdinates of a point in a plane, consisting of the three ratios which the three distances of the point from three fixed lines have one to another.

n. 1 (context mathematics English) The coordinates of a point in a plane, measured as its Cartesian distance from the origin and the angle measured anticlockwise/counterclockwise from the x-axis to a line joining the point to the origin. 2 (context mathematics English) The coordinates of a point in three-dimensional space, measured as its Cartesian distance from the origin, the angle measured from the z-axis to a line joining the point to the origin, and the angle measured anticlockwise from the x-axis to this line.