 sack

a traditional unit of volume, typical measure is 3 bushels (about 105.7
liters based on the U.S. bushel, or 109.1 liters based on the British Imperial
bushel).

a traditional unit of weight. In the U.S., a sack of salt is traditionally
equal to 215 pounds, a sack of cotton 140 pounds, and a sack of flour 100
pounds. A sack of concrete is traditionally 94 pounds in the U.S., 87.5 pounds
in Canada.
 sao

a traditional unit of land area in Vietnam. It is equal to 360 square
meters (430.6 square yards) in many places, but 500 square meters (598.0 square
yards) in others.
 scale

a measure describing the resolution of a map, architectural plan, or some
similar document. For example, "1:200 000 scale" in map. In general, 1:n
scale means that 1 unit of distance on the map or plan represents n of
the same units in fact. The notation 1:n is simply another way of
writing the ratio 1/n.
 scheffel or schepel

traditional units of dry volume. scheffel (in German) equals 50 liters (1.4189
U.S. bushels) and the schepel (in Dutch)10 liters (0.2838 U.S. bushels). Both
words are usually translated "bushel" in English.
 schock

a traditional German unit of quantity equal to 60.
 schtoff

a traditional Russian unit of volume, equals to 10 charki, about 1.23
liters or 1.30 U.S. liquid quarts.
 score

a traditional unit of quantity equal to 20.
 scruple

a unit of weight in the traditional (troy) system used by English apothecaries,
equal to 20 grains, 1/24 troy ounce or approximately 1.2960 gram. The name of
the unit is from the Latin scrupulus, meaning a small, sharp stone.
 se

a traditional Japanese unit of area equal to about 99 square meters or 118.4
square yards.
 seah

an ancient Hebrew measure of both liquid and dry volume, was equal to about
13.44 liters (about 3.55 U.S. liquid gallons or 2.96 British Imperial gallons).
 seam

a traditional unit of volume. A seam of grain was 8 bushels: equivalent to
290.95 liters based on the British Imperial bushel, or 281.91 liters based on
the older U.S bushel. The AngloSaxon word "seam" meant the load of a
pack animal. The seam continued in use to the early nineteenth century, but in
later years it was more often called a quarter.
 sea mile

another name for the nautical mile.
 season

a portion of a year. The word is derived from a Latin word meaning the
time for sowing, originally meant one of the periods of the agricultural year,
more specifically as a unit of time equal to 1/4 year.
 second

a fundamental unit of time in all measuring systems. The name simply means that
this unit is the second division of the hour, the minute being the first.

a unit of angular measure equal to 1/60 arcminute. This unit is also called the
arcsecond to distinguish it from the second of time. One
second is very small: there are 1,296,000 seconds in a circle.
 seconddayfoot

a unit of volume for water sometimes used in U.S. hydrology. A seconddayfoot
is the volume of water accumulated in one day by a flow of one cubic foot per
second; this is equal to exactly 86 400 cubic feet or about 2446.58 cubic
meters, approximately 1.9835 acre feet. Also known as the daysecondfoot.
 secondfoot

an informal name for the cubic foot per second as a flow rate for water.
 section

a traditional unit of area in the U.S., equals to 1 square mile. It is used by
the U.S. Public Land Survey System, for most states except for the original 13
states, Alaska, and Hawaii.
 seemeile

the German name for the nautical mile.
 seer

a traditional weight unit in India and South Asia. The seer equals 1/40 maund,
The official size in India was 2.057 15 pounds or 0.9331 kilogram. In Pakistan,
the seer is now considered equal to the kilogram. The unit is sometimes spelled ser.

a traditional unit of dry volume in northern India, equal to a little more than
a liter. This is roughly the volume of a seer of grain.
 seidel

a traditional unit of liquid volume in Austria, was equal to about 354
milliliters, about 12.0 U.S. fluid ounces or about 12.5 British fluid ounces.
 semester (sem)

an informal unit of time. The word semester comes from the Latin words for "six
months," and originally a semester was equal to 6 months or 1/2 year.
However, it means half the academic year at a school or college, a
period of time which can vary from 15 to 21 weeks.
 semester hour

a unit of academic credit, equals to one semester's study for a period of one
hour per week. However, "academic hours" slightly shorter than regular hours
(often 50 or 55 minutes per class) are typically used in calculations.
 semi

a common English prefix meaning 1/2. semi is diffrent from bi, it means
"twice every" or "every half."; for something that happens once
every two time units, use bi.
 semibreve

a unit of relative time in music equal to 1 whole note or 1/2 breve
 semiquaver

a unit of relative time in music equal to 1/16 whole note or 1/32 breve.
 semitone

a unit used in music to describe the ratio in frequency between notes.
 sennight

an old English name for a week, formed as a contraction of seven nights .
 septennium

a unit of time equal to 7 years.
 septet

a unit of quantity equal to 7.
 septuple, septuplet

a group of 7 items, especially 7 identical items; the word septuplet is also
used for one member of the group.
 sestet

another name for a sextet, a unit of quantity equal to 6. This spelling is used
in poetry to describe a sixline stanza and is sometimes used in music for an
ensemble of 6 instruments.
 seventh

a unit used in music to describe the ratio in frequency between notes. Two
notes differ by one seventh if the higher note has frequency exactly 15/8 times
the frequency of the lower one.
 sextarius

a Roman unit of liquid volume. The word means "sixth", and the unit was equal
to 1/6 congius, about 530 milliliters, very close to the capacity of the
British and U.S. pint.
 sextet

a unit of quantity equal to 6.
 sextuple, sextuplet

a group of 6 items, especially 6 identical items; the word sextuplet is also
used for one member of the group.
 shaku

a Japanese word meaning "measure" or "scale", it could be used
as different units. As a unit of distance, the shaku is the
Japanese foot, equal to about 30.30 centimeters or 11.93 inches; As a
unit of area, the shaku equals 330.6 square centimeters (51.24 square
inches); As a unit of volume, the shaku equals about 18.04 milliliters
(0.61 U.S. fluid ounce).
 shekel

an ancient Hebrew unit of weight. The shekel was the Hebrew version of a
Babylonian unit used throughout the Middle East. A frequently quoted equivalent
is 252 grains, or 0.5760 ounce (avoirdupois) or about 16.33 grams, but other
sources quote a value of 8.4 grams or various values between these two.
 sheng

a traditional unit of liquid volume in China. Like the Indian seer, the sheng
is a little more than a liter, 1.035 liter (1.094 U.S. quart).
 shift

a unit of time equal to the scheduled period of work at a factory or other
place of business. Businesses operating on a 24hour basis typically organize
the day into three daily shifts of 8 hours each.
 sho

a traditional Japanese unit of liquid volume. The sho equals 1.8039 liter,
which is 1.9061 U.S. quarts or 1.5872 British imperial quarts.
 shock or shook

a unit of quantity equal to 5 dozen, 3 score, or 60. The unit is more common in
German, a bundle of 60 barrel staves is traditionally called a shock.
 short ton

a common name for the U.S. ton (2000 pounds).
 sixth

a unit used in music to describe the ratio in frequency between notes. Two
notes differ by one minor sixth if the higher note has
frequency exactly 8/5 times the frequency of the lower one, or by a major
sixth if the higher note has frequency exactly 5/3 times the
frequency of the lower one.
 slug

a unit of mass in the English footpoundsecond system. One slug is the mass
accelerated at 1 foot per second per second by a force of 1 pound, equal
to 32.174 04 pounds (14.593 90 kilograms).
 skock

a traditional Swedish unit of quantity equal to 60. See shock above.
 span

a traditional unit of distance equal to 9 inches (approximately 22.9
centimeters) or 1/4 yard. This distance represents the span of a man's hand
with fingers stretched out as far as possible.
 square

the prefix of a unit of area, means length unit by the same length
unit; e.g. square meter (m^{2}).
 stang

a traditional Welsh unit of land area, generally equals to 3240 square yards,
0.6694 acre, or 0.2709 hectare.
 step

a traditional unit of distance, equal to 1/2 pace. 8 steps are made every 5
yards, using this shorter step is called marching "8 by 5."

a unit used in music to describe the ratio in frequency between notes.
 steradian (sr)

the standard unit of solid angle measure in mathematics. Just as there are 2
pi radians in a circle, there are 4pi
steradians in a sphere.
 stere

a metric unit of volume, equals to one cubic meter or one kiloliter (about
35.3147 cubic feet or 1.307 95 cubic yards). The name comes from the
Greek stereos, solid.
 sthene

a metric unit of force. One sthene is the force required to accelerate a mass
of one tonne at a rate of 1 m/s^{2}. Thus the sthene is equal to the
kilonewton. The name comes from the Greek word sthenos, strength.
 stone

a traditional British unit of weight, originally varied in size: a stone
of sugar was traditionally 8 pounds, while a stone of wool could be as much as
24 pounds. The stone was finally standardized at 14 pounds avoirdupois or
approximately 6.350 29 kilograms, 1/2 quarter or 1/8 hundredweight.
 stride

another name for a pace.
 strike

a traditional British unit of volume, equivalent is 2 imperial bushels (roughly
2.5 cubic feet or 73 liters).
 stunde

the German word for the hour. In Switzerland, the stunde is also a unit of
distance defined to be 4800 meters (2.983 miles).
 super foot

a British commercial unit of area equal to one square foot. in Australia and
New Zealand a super foot is a unit of volume for timber or lumber, equal to the
volume of a board one foot square and one inch thick. This unit is the same as
the North American board foot.
 surface foot

another name for a linear foot.
 survey foot

a former U.S. definition of the foot as exactly 1200/3937 meter or about 30.480
060 96 centimeters. This was the official U.S. definition of the foot from 1866
to 1959; it makes the meter equal exactly 39.37 inches. In 1959 the survey foot
was replaced by the international foot, equal to exactly 30.48
centimeters.
