Dictionary Definition
length
Noun
1 the linear extent in space from one end to the
other; the longest horizontal dimension of something that is fixed
in place; "the length of the table was 5 feet"
2 continuance in time; "the ceremony was of short
duration"; "he complained about the length of time required" [syn:
duration]
3 the property of being the extent of something
from beginning to end; "the editor limited the length of my article
to 500 words"
4 size of the gap between two places; "the
distance from New York to Chicago"; "he determined the length of
the shortest line segment joining the two points" [syn: distance]
5 a section of something that is long and narrow;
"a length of timber"; "a length of tubing"
User Contributed Dictionary
English
Etymology
lengþuPronunciation
 , /lɛŋθ/, /lENT/
Noun
 The measurement
of distance along the
longest dimension of
an object.
 Robert Frost
 Happiness makes up in height for what it lacks in length.
 Robert Frost
 In the context of "horse racing": The length of a horse, used to indicate the distance between horses at the end of a race.
 Magnitude. gloss English
 The distance down the pitch that the ball bounces on its way to the batsman.
Translations
measurement of distance
 Albanian: gjatësi
 Arabic: طول
 Aramaic:
 Breton: hed
 Bulgarian: дължина (dәlžiná)
 Croatian: duljina
 Czech: délka
 Dutch: lengte
 Esperanto: longo
 Finnish: pituus
 French: longueur
 German: Länge
 Hebrew: אורך
 Hungarian: hossz
 Irish: fad
 Italian: lunghezza
 Japanese: 長さ (nagasa), 全長 (zenchou)
 Kurdish:
 Sorani: درێژایی
 Lithuanian: ilgis , ilgumas
 Occitan: longor
 Polish: długość
 Portuguese: comprimento
 Russian: длина
 Slovak: dĺžka
 Spanish: largo
 Swedish: längd
 Telugu: పొడవు (poDavu)
 Turkish: uzunluk
length of a horse
 German: Pferdelänge
 Turkish: boy
Extensive Definition
Length is the long dimension of any object. The
length of a thing is the distance between its ends, its linear
extent as measured from end to end. This may be distinguished from
height, which is vertical
extent, and width or breadth, which are the distance from side to
side, measuring across the object at right angles to the length. In
the physical sciences and engineering, the word "length" is
typically used synonymously with "distance", with symbol l or
L.
Length is a measure of one dimension, whereas
area is a measure of two
dimensions (length squared) and volume is a measure of three
dimensions (length cubed). In most systems of measurement, length
is a fundamental
unit, from which other units are derived.
Units of length
In the physical sciences and engineering, when one speaks of "units of length", the word "length" is synonymous with "distance". There are several units that are used to measure length. Units of length may be based on lengths of human body parts, the distance travelled in a number of paces, the distance between landmarks or places on the Earth, or arbitrarily on the length of some fixed object.In the
International System of Units (SI), the basic unit
of length is the metre and
is now defined in terms of the speed of
light. The centimetre and the kilometre, derived from the
metre, are also commonly used units. In U.S.
customary units, English or Imperial
system of units, commonly used units of length are the inch, the foot,
the yard, and the mile.
Units used to denote distances in the vastness of
space, as in astronomy, are much longer
than those typically used on Earth and include the astronomical
unit, the lightyear, and
the parsec.
Units used to denote microscopically small
distances, as in chemistry, include the micron
and the ångström.
Length of moving rods
In the context of "section": While the length of a resting rod can be measured by direct comparison with a measuring rod, this comparison cannot be performed while the rod is moving. In this case we define its moving length as the distance between its two endpoints at a given instance.If the world lines of
the two endpoints of the rod expressed in the coordinates of an R
\, inertial reference frame are

 \mathbf x_1(t) = (t,x_1(t),y_1(t),z_1(t))\,
and

 \mathbf x_2(t) = (t,x_2(t),y_2(t),z_2(t))\, ,
then the length of the rod in this reference
frame at the t \, instance is

 l_R(t) = \sqrt.
Since in special
relativity the relation of simultaneity
depends on the chosen frame of reference, the length of moving rods
also depends.
See also
 Distance
 Dimension
 Orders of magnitude (length)
 How round is your circle? Contains a chapter giving the history of length and angle measurement.
 Smoot
length in Arabic: طول
length in Min Nan: Tn̂gté
length in Catalan: Longitud (física)
length in Czech: Délka
length in Welsh: Hyd
length in Danish: Længde
length in German: Längenmaß
length in Modern Greek (1453): Μήκος
length in Esperanto: Longo
length in French: Longueur
length in Korean: 길이
length in Croatian: Duljina
length in Interlingua (International Auxiliary
Language Association): Longitude
length in Icelandic: Lengd
length in Italian: Lunghezza
length in Hebrew: אורך
length in Latin: Longitudo
length in Latvian: Garums
length in Hungarian: Hossz
length in Malay (macrolanguage): Panjang
length in Dutch: Lengte (meetkunde)
length in Japanese: 長さ
length in Norwegian: Lengde
length in Portuguese: Comprimento
length in Romanian: Lungime
length in Quechua: Karu kay
length in Russian: Длина
length in Albanian: Gjatësia
length in Simple English: Length
length in Slovenian: Dolžina
length in Serbian: Дужина
length in Finnish: Pituus
length in Swedish: Längd
length in Tamil: நீளம்
length in Thai: มาตราวัดความยาว
length in Vietnamese: Chiều dài
length in Turkish: Uzunluk birimleri
length in Ukrainian: Довжина
length in Yiddish: לענג
length in Chinese: 长度
Synonyms, Antonyms and Related Words
aesthetic distance, amplitude, area, at full length, at length, at
long last, bigness,
body, breadth, bulk, caliber, clearance, compass, completely, coverage, deep space, depth, depths of space, diameter, dimension, dimensions, distance, divergence, duration, eventually, exhaustively, expanse, expansion, extension, extensively, extent, farness, finally, fully, gauge, girth, greatness, height, in detail, infinity, interminably, largeness, leeway, lightyears, magnitude, margin, mass, measure, measurement, mileage, orbit, panorama, parsecs, period, perspective, piece, proportion, proportions, purview, radius, range, reach, realm, remoteness, scale, scope, separation, size, space, span, spread, stretch, stride, term, thoroughly, ultimately, volume, way, ways, width