NON-SI UNIT PREFIX

There exist several 'unit prefixes' used like the SI prefixes, but that are not part of the SI system.
Some of these were never part of any actual system of measurement. A few were proposals that were rejected. None are in common use, and many of the powers of ten they represent are already taken by SI prefixes. Sometimes a prefix is simply mistaken; ''dk'' has been passed off as an abbreviation for ''deka''.
One such prefix is ''bronto'', used in the fake term ''brontobyte''. References on the World Wide Web suggest meanings of the bronto prefix to be variously any of 10¹⁵, 10²¹, 10²⁴, or 10²⁷. SI has already produced standard prefixes for 10¹⁵ (peta), 10²¹ (zetta) and 10²⁴ (yotta).

Contents

Proposed and unofficial prefixes

Obsolete prefixes

Proposed systems

References

External links

Proposed and unofficial prefixes

There are many other unofficial prefixes. Some of them appear to come from a numerical Greek root indicating the power of 1000 the prefix means. Others are based on the names of the Marx Brothers. These prefixes are as follows:

Prefix	Purported meaning
udeka- (U)	1036
udekta- (U)	1036
una-	1033
vendeka- (V)	1033
weka- (W)[1]	1030
wekta- (W)	1030
decetta-	1030
dea-	1030
grouchi-	1030
nea-	1027
xenna- (X)	1027
xenta- (X)	1027
novetta-	1027
harpi-	1027
lotta- (L)	1027
nova- (N)	1027
taxo- (Tx)[2]	1027
otta-	1024
hepa-	1021
ento-	10−21
fito-	10−24
syto-	10−27
xenno- (x)	10−27
novemo-	10−27
empto- (e)'Ask A Scientist' Time Terminology.Emptosecond pulses.	10−27
harpo- http://backpan.perl.org/authors/id/P/PI/PIP/Time-Fields-1.0.3CCA4Eh.readme	10−27
lotto- (l)	10−27
novo- (n)	10−27
millikan- (mkan)	10−27
tredo-	10−30
weko- (w)	10−30
decemo-	10−30
groucho- http://backpan.perl.org/authors/id/P/PI/PIP/Time-Fields-1.0.3CCA4Eh.readme	10−30
revo-	10−33
vendeko- (v)	10−33
zeppo- http://backpan.perl.org/authors/id/P/PI/PIP/Time-Fields-1.0.3CCA4Eh.readme	10−33
gummo- http://backpan.perl.org/authors/id/P/PI/PIP/Time-Fields-1.0.3CCA4Eh.readme	10−36
chico- http://backpan.perl.org/authors/id/P/PI/PIP/Time-Fields-1.0.3CCA4Eh.readme	10−39

Obsolete prefixes

Some prefixes were used in older versions of the metric system but are not part of the modern metric system, the SI.
The prefixes 'myria' (''ma'' or ''my'', for 10000) and 'myrio' (''mo'', for 1/10000) came from the Greek μύριοι (mýrioi) 'ten thousand'. Part of the original metric system adopted by France in 1795, they were not retained when the SI prefixes were agreed internationally by the 11th CGPM in 1960.
They were rarely used, though the myriameter (10 km) is occasionally encountered in 19th-century train tariffs. In Sweden (and possibly other countries), the myriameter is still very common in everyday use, simplifying the way of denoting long distances (although not recognized or used officially). In Swedish, this unit is called 'mil', not seldom causing confusion when Swedes use the English word 'mile' (incorrectly) as a direct translation.
Of units customarily used in trade in France, the myriagramme (10 kg) was the metric replacement for the avoirdupois unit of the quarter (25 pounds) (whereas the Myriogramme is also a genus of seaweed).
Also obsolete are metric ''double'' prefixes, such as those formerly used in micromicrofarads, hectokilometres, micromillimetres, and so on.

Proposed systems

A proposal by Jim Blowers describes the naming scheme as follows:
zetta is Z + -etta, which is an alteration of septi-, meaning 7, as 21 is 7 groups of three. yotta is Y + -otta, an alteration of octo-, meaning 8. The pattern here is that we go backwards from the beginning of the alphabet, starting with z and y, and we follow it up with an alteration of the Greek or Latin for the next number. According to this pattern, the next ending should be xona-, since X comes before Y in the alphabet, and 9 is noni- in Latin. Similarly, 10³⁰ should be weka-, since W precedes X and 10 is deka in Greek.

Factor	Name	Symbol		Factor	Name	Symbol
10−1	deci-	d		101	deca-	da
10−2	centi-	c		102	hecto-	h
10−3	milli-	m		103	kilo-	k
10−6	micro-	μ		106	mega-	M
10−9	nano-	n		109	giga-	G
10−12	pico-	p		1012	tera-	T
10−15	femto-	f		1015	peta-	P
10−18	atto-	a		1018	exa-	E
10−21	zepto-	z		1021	zetta-	Z
10−24	yocto-	y		1024	yotta-	Y
10−27	xonto-	x		1027	xona-	X
10−30	wekto-	w		1030	weka-	W
10−33	vunkto-	v		1033	vunda-	V
10−36	unto-	u		1036	uda-	U
10−39	trekto-	td		1039	treda-	TD
10−42	sotro-	s		1042	sorta-	S
10−45	rimto-	r		1045	rinta-	R
10−48	quekto-	q		1048	quexa-	Q
10−51	pekro-	pk		1051	pepta-	PP
10−54	otro-	o		1054	ocha-	O
10−57	nekto-	nk		1057	nena-	N
10−60	mikto-	mi		1060	minga-	MI
10−63	lunto-	l		1063	luma-	L

There have also been proposals to use the units of one of these systems with prefixes of a different base than ten, e.g. binary, duodecimal or hexadecimal.

References

1. Proposals for an extended system of units.
2. 'Ask A Scientist' Time Terminology.

External links

★ Proposal to extend system of units from 10⁻⁶³ to 10⁶³

★ BBC article suggesting that a brontobyte is 10²⁷ bytes

★ Sybase article suggesting that a brontobyte is 10²⁴ or 10²⁷ bytes (Note article's table a few pages down. Note also it mistakenly places 1 terabyte = 1,000 megabytes. It should be 1 terabyte = 1,000 gigabytes. Also yottabyte is shown incorrectly as zottabyte. With those corrections, it also is clearly 10²⁷.)

★ Article suggesting that a brontobyte is 10²¹ bytes

★ Article suggesting that a brontobyte was 10¹⁵ bytes before the creation of the prefix peta- (Article is of dubious authority... suggests that Greek letters ν, π, and φ are SI prefixes for nano-, pico-, and femto-, instead of n, p, and f.)

★ Article suggesting that brontobyte is 10²⁷ bytes

★ Moerner Lab Single-Molecule Research Page (Jokingly defines 1 guacamole = 1 / (''Avocado's'' number) of moles. Scientific paper with reference)

★ Jargon file entry for "quantifiers" Claims that groucho, harpo, grouchi, and harpi (based on the Marx Brothers' names) have gained the general approval of Usenet.

★ vendeka.org website Support for vendeka = 10³³

★ Final Answers: Measurement and Units Large table of units