# Distance

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## distance

1. Geometry
a. the length of the shortest line segment joining two points
b. the length along a straight line or curve
2. Horse racing
a. Brit a point on a racecourse 240 yards from the winning post
b. Brit any interval of more than 20 lengths between any two finishers in a race
c. US the part of a racecourse that a horse must reach in any heat before the winner passes the finishing line in order to qualify for later heats
3. go the distance Boxing to complete a bout without being knocked out
4. the distant parts of a picture, such as a landscape
5. middle distance
a. (in a picture) halfway between the foreground and the horizon
b. (in a natural situation) halfway between the observer and the horizon
6. Athletics relating to or denoting the longer races, usually those longer than a mile

## Distance

distance in depth between servicemen, guns, vehicles, and subunits or units (ships) when formed in ranks, on the march (cruise), or in combat formation and also between aircraft when flying in formation or in a combat formation.

## Distance

an important geometric concept whose meaning depends on the kind of entities for which it is defined. The distance between two points is the length of the line segment joining the points. The distance from a point to a line or a plane is the length of the perpendicular from this point to the line or plane. The distance between two parallel lines or planes is the length of a common perpendicular to the lines or planes. The distance between two nonintersecting nonparallel lines in space is equal to the distance between the parallel planes in which the lines lie—that is, the length of the line segment that joins the lines and is perpendicular to both.

## distance

[′dis·təns]
(mathematics)
A nonnegative number associated with pairs of geometric objects.
The spatial separation of two points, measured by the length of a hypothetical line joining them.
For two parallel lines, two skew lines, or two parallel planes, the length of a line joining the two objects and perpendicular to both.
For a point and a line or plane, the length of the perpendicular from the point to the line or plane.
(mechanics)
The spatial separation of two points, measured by the length of a hypothetical line joining them.
References in periodicals archive ?
5Mm 6 Close Focusing Distance: 8M 7 Weight: 910G 8 Length: 179Mm 9 Width: 197Mm 10 Interpupillary Distance Adjustment: 56-72Mm 11 Exit Pupil: 4.
The service has noted that the two 'particular areas of difficulty' that optical professionals should take note of today are the rise in complaints from those who have their sight test at one practice, then take their prescription to a different practice or source to have it dispensed--the second is when a practitioner refuses to measure interpupillary distance (PD), a controversy which was featured on BBC Radio 4's consumer rights programme, You and Yours this summer (OT, September 3).
Key features for both models include roof-prism design, interpupillary distance lock, textured brown armor coating, retractable twist-up three-position eyecups, neoprene neck strap, carry case and custom eyepiece and objective lens covers.

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