# plane

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Related to median plane: frontal plane, dorsal plane

## plane,

in mathematics, flat surface of infinite extent but no thickness. An example of a plane, or more exactly of a bounded portion of a plane, is the surface forming one face, or side, of a cube. A plane is determined, or defined, by any of the following: (1) three points not in a straight line; (2) a straight line and a point not on the line; (3) two intersecting lines; or (4) two parallel lines. Two straight lines in space do not usually lie in the same plane. For a given plane in space, a line can either lie outside and parallel to it, intersect the plane in a single point, or lie entirely in the plane; if more than one point of a straight line lies in the plane, then the entire line must lie in the plane.

## Plane

The simplest kind of two-dimensional surface, generated by the path of a straight line and defined by its length and width. The fundamental property of a plane is its shape and surface characteristics.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

## Plane

one of the fundamental concepts in geometry. In a systematic exposition of geometry, a plane is usually considered as an initial concept, which is only indirectly defined by the axioms of geometry. Its characteristic properties include the following: (1) A plane is a surface such that every line connecting any two of its points lies entirely within the surface. (2) A plane is a set of points equidistant from two given points.

### REFERENCES

Efimov, N. V. Vysshaia geometriia, 5th ed. Moscow, 1971.
Hilbert, D. Osnovaniia geometrii. Moscow-Leningrad, 1948. (Translated from German.)

## Plane

a wood-shaving tool consisting of a wooden or metal stock, a cutter, and a wedge. The earliest planes, discovered in Pompeii, date to the first century A.D. Little use was made of the plane in ancient times and in the Middle Ages, the principal planing tool being the drawknife; widespread use of the plane began in the 15th and 16th centuries.

There are several types of planes, classified according to the type of planing (flat or profile planing), the stock size, and the cutter profile and angle adjustment. Jack planes are used for rough, flat planing with a rounded cutting blade. Single- and double-iron planes with chip breakers and trying planes, which are elongated and have two handles, are used for finish planing. Jointer planes and long planes, the latter distinguished by extreme length of the stock, are used for finish planing, for planing large, flat areas using a straight edge to check for the finish desired, and for fitting parts. Especially thin layers of wood are removed with smoothing planes. Toothing planes are used for making fine grooves on the surfaces of parts to be glued. Rabbets can be cut with rabbet planes and trimmed with fillister planes. Matching planes are used for making grooves, and router planes cut trapeziform slots against the grain. Irregularly shaped patterns on the faces of parts are worked with molding planes. Compass planes have a curved stock and are used in working curved (concave or convex) surfaces. Electric-powered hand planes are also used.

## plane

[plān]
(electronics)
Screen of magnetic cores; planes are combined to form stacks.
(design engineering)
A tool consisting of a smooth-soled stock from the face of which extends a wide-edged cutting blade for smoothing and shaping wood.
(mathematics)
A surface such that a straight line that joins any two of its points lies entirely in that surface.
In projective geometry, a triple of sets (P, L, I) where P denotes the set of points, L the set of lines, and I the incidence relation on points and lines, such that (1) P and L are disjoint sets, (2) the union of P and L is nonnull, and (3) I is a subset of P × L, the cartesian product of P and L.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

## plane

plane, 1
1. A tool for smoothing wood surfaces; consists of a smooth soleplate, from the under-side of which projects slightly the cutting edge of an inclined blade; there is an aperture in front of the blade for the shavings to escape.
2. A surface, any section through which by a like surface is a straight line.
3. Of a column, the surface of a longitudinal section through the axis of the column.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.

## plane

1
1. Maths a flat surface in which a straight line joining any two of its points lies entirely on that surface
2.
a. short for aeroplane
b. a wing or supporting surface of an aircraft or hydroplane
3. Maths (of a curve, figure, etc.) lying entirely in one plane

## plane

2
1. a tool with an adjustable sharpened steel blade set obliquely in a wooden or iron body, for levelling or smoothing timber surfaces, cutting mouldings or grooves, etc.
2. a flat tool, usually metal, for smoothing the surface of clay or plaster in a mould
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
(13) Length of the cranium from the most aboral point on the vertex of the cranium in the median plane to the (dorso) aboral point of the foramen infraorbitale A-If (Akrokranion --Infraorbitale).
(6) Angular height of the neurocranium (neurocranium length) from the median point of the naso-frontal suture to the orobasal border of the foramen magnum in the median plane N-B (Nasion--Basion).
(3) Length of the cranium base (basal length) from the orobasal border of the foramen magnum in the median plane to the median point of the line joining the most oral points of the praemaxillae B-P (Basion--Prosthion).
(4) Length of the cranium from the orobasal border of the foramen magnum in the median plane to the median point of the line joining the oral points of the alveoli of the foremost cheek teeth (short skull length) B-Pm (Basion--Praemolare).
Figure 2(a) presents an arrangement of stimuli which are both co-planar and orthogonal to the participant's median plane as they were used in the earlier investigations (e.g.
This suggests that this discrepancy in strength varies with the orientation of the plane containing the stimulus, declining with the decrease of the angle which this plane makes with the participant's median plane. This effect should also be demonstrable when only one stimulus is presented at a time.
This effect enables the observer to distinguish between two orientations of the lamellae that are symmetrical about their median plane, for example a lamella pointing towards the north-east and th e same lamella pointing towards the north-west.
They were set in the least irregular part of the quadrant, with the exception of quadrant 3 in which the horizontal wire crossed the median plane at the level of the pyriform aperture of the nasal cavity, supported on the root of the right and left inferior nasal conchae (Fig.
B, The light marks indicate the median plane of the skull (white arrow).
The masker could be positioned at either of two locations within the median plane. When the masker was directly in front of the subject (0 deg azimuth, 0 deg elevation), the signal could originate from any of the following locations within the median plane: 0 deg azimuth, -10 deg elevation; 0 deg azimuth, 0 deg elevation; 0 deg azimuth, 10 deg elevation; 0 deg azimuth, 45 deg elevation; 0 deg azimuth, 90 deg elevation; 180 deg azimuth, 45 deg elevation; and 180 deg azimuth, 0 deg elevation.
Threshold signal-to-noise ratios for conditions in which both the signal and the masker were presented from within the median plane are plotted as a function of the elevation of the signal in Figures 3 and 4.
Indeed, the patterns of results for the high-frequency stimuli in the horizontal plane [ILLUSTRATION FOR FIGURE 1 OMITTED] and in the median plane (Figure 3) are quite similar, even though the interaural differences should be relatively small within the median plane.

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