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Deca-
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Deca-" .
This article is about the SI prefix. For other uses, see
Deca .
deca- or deka- [1] is an SI prefix (symbol da ) in the SI system of units, also a numerical prefix (from Greek δέκα), denoting a factor of 101 or ten .
The prefix was a part of the original metric system in 1795 . It is not in very common usage, although the decapascal is occasionally used by audiologists. The decanewton is also encountered occasionally, probably because it is an SI approximation of the kilogram-force .
Before the symbol was standardized as da with the introduction of the SI in 1960, various other symbols were more common, such as "dk", "D", and "Da".
SI prefixes
1000m
10n
Prefix
Symbol
Since[1]
Short scale
Long scale
Decimal
10008
1024
yotta-
Y
1991
Septillion
Quadrillion
1 000 000 000 000 000 000 000 000
10007
1021
zetta-
Z
1991
Sextillion
Trilliard
1 000 000 000 000 000 000 000
10006
1018
exa-
E
1975
Quintillion
Trillion
1 000 000 000 000 000 000
10005
1015
peta-
P
1975
Quadrillion
Billiard
1 000 000 000 000 000
10004
1012
tera-
T
1960
Trillion
Billion
1 000 000 000 000
10003
109
giga-
G
1960
Billion
Milliard
1 000 000 000
10002
106
mega-
M
1960
Million
1 000 000
10001
103
kilo-
k
1795
Thousand
1 000
10002/3
102
hecto-
h
1795
Hundred
100
10001/3
101
deca-
da
1795
Ten
10
10000
100
(none)
(none)
NA
One
1
1000−1/3
10−1
deci-
d
1795
Tenth
0.1
1000−2/3
10−2
centi-
c
1795
Hundredth
0.01
1000−1
10−3
milli-
m
1795
Thousandth
0.001
1000−2
10−6
micro-
µ
1960[2]
Millionth
0.000 001
1000−3
10−9
nano-
n
1960
Billionth
Milliardth
0.000 000 001
1000−4
10−12
pico-
p
1960
Trillionth
Billionth
0.000 000 000 001
1000−5
10−15
femto-
f
1964
Quadrillionth
Billiardth
0.000 000 000 000 001
1000−6
10−18
atto-
a
1964
Quintillionth
Trillionth
0.000 000 000 000 000 001
1000−7
10−21
zepto-
z
1991
Sextillionth
Trilliardth
0.000 000 000 000 000 000 001
1000−8
10−24
yocto-
y
1991
Septillionth
Quadrillionth
0.000 000 000 000 000 000 000 001
The metric system was introduced in 1795 with six prefixes. The other dates relate to recognition by a resolution of the CGPM .
The 1948 recognition of the micron by the CGPM was abrogated in 1967.
References
^ Guide for the Use of the International System of Units (SI), 1995, NIST Special Publication 811[1]
See also
External links