Deci-

French 1 decime coin, equal to ⁠1/10⁠ of a franc. First Republic.

Deci (symbol d) is a decimal unit prefix in the metric system denoting a factor of one tenth. Proposed in 1793, ^[1] and adopted in 1795, the prefix comes from the Latin decimus, meaning "tenth". Since 1960, the prefix is part of the International System of Units (SI). ^{[2] [3]}

A frequent use of the prefix is in the unit deciliter (dl), common in food recipes; many European homes have a deciliter measure for flour, water, etc. A common measure in engineering is the unit decibel for measuring ratios of power and root-power quantities, such as sound level and electrical amplification.

Example

• The diameter of a compact disc is about 12 centimetres or 1.2 decimetres. ^[4]

SI prefixes

• v
• t
• e

Prefix		Base 10	Decimal	Adoption [nb 1]
Name	Symbol
quetta	Q	1030	1000000000000000000000000000000	2022 [5]
ronna	R	1027	1000000000000000000000000000
yotta	Y	1024	1000000000000000000000000	1991
zetta	Z	1021	1000000000000000000000
exa	E	1018	1000000000000000000	1975 [6]
peta	P	1015	1000000000000000
tera	T	1012	1000000000000	1960
giga	G	109	1000000000
mega	M	106	1000000	1873
kilo	k	103	1000	1795
hecto	h	102	100
deca	da	101	10
—	—	100	1	—
deci	d	10−1	0.1	1795
centi	c	10−2	0.01
milli	m	10−3	0.001
micro	μ	10−6	0.000001	1873
nano	n	10−9	0.000000001	1960
pico	p	10−12	0.000000000001
femto	f	10−15	0.000000000000001	1964
atto	a	10−18	0.000000000000000001
zepto	z	10−21	0.000000000000000000001	1991
yocto	y	10−24	0.000000000000000000000001
ronto	r	10−27	0.000000000000000000000000001	2022 [5]
quecto	q	10−30	0.000000000000000000000000000001
Notes Prefixes adopted before 1960 already existed before SI. The introduction of the CGS system was in 1873.

References

1. Commission temporaire de Poids & Mesures rêpublicaines, En exécution des Décrets de la Convention Nationale (1793). Instruction abrégée sur les mesures déduites de la grandeur de la Terre; uniformes pour toute la Rêpublique, et sur les Calculs relatifs à leur division décimale (in French) (Edition originale ed.). Paris, France: De l´imprimerie nationale exécutive du Louvre. Retrieved 2015-10-09.
2. The International System of Units (Si): The Metric System. DIANE Publishing. 1992. p. 30. ISBN   9780941375740.
3. "Resolution 12 of the 11th CGPM". BIPM. 1960. Archived from the original on 2020-04-08. Retrieved 2020-05-14.
4. "Universcale: From the nanoworld to the universe — The worlds we measure using our infinite yardstick". Nikon. 2013. Archived from the original on 2017-02-08. Retrieved 2017-02-08.
5. "On the extension of the range of SI prefixes". 18 November 2022. Retrieved 5 February 2023.
6. "Metric (SI) Prefixes". NIST.