Hecto

hecto- (symbol h) is a SI prefix in the SI system of units denoting a factor of 10² (100).

Adopted in 1795, it comes from the Greek ἑκατόν hekaton, meaning hundred.

It is rarely used, except for certain specific applications:

hectare, 100 ares, a very common measure of land area.
hectopascal, in meteorology, for atmospheric pressure, the modern equivalent of the traditional millibar.
hectolitre, in agriculture, for liquids (notably wine) and bulk commodities (e.g. grain).
hectogram, in agronomy, for quantities of animal feed (hectogram/animal) and for measures of agricultural productivity (hectogram/hectare); also used in Italy, abbreviated as etto, for retail sale of cold cuts and meat.
hectometre, in radio astronomy, occasionally used to indicate a radio band by wavelength

SI prefixes
10ⁿ	Prefix	Symbol	Short scale	Long scale	Decimal equivalent in SI#SI writing style > SI writing style
10²⁴	yotta	Y	Septillion	Quadrillion	1 000 000 000 000 000 000 000 000
10²¹	zetta	Z	Sextillion	Trilliard (thousand trillion)	1 000 000 000 000 000 000 000
10¹⁸	exa	E	Quintillion	Trillion	1 000 000 000 000 000 000
10¹⁵	peta	P	Quadrillion	Billiard (thousand billion)	1 000 000 000 000 000
10¹²	tera	T	Trillion	Billion	1 000 000 000 000
10⁹	giga	G	Billion	Milliard (thousand million)	1 000 000 000
10⁶	mega	M	Million		1 000 000
10³	kilo	k	Thousand		1 000
10²	hecto	h	Hundred		100
10¹	deca, deka	da	Ten		10
10⁰	(none)	(none)	One		1
10⁻¹	deci	d	Tenth		0.1
10⁻²	centi	c	Hundredth		0.01
10⁻³	milli	m	Thousandth		0.001
10⁻⁶	micro	µ (u)	Millionth		0.000 001
10⁻⁹	nano	n	Billionth	Milliardth	0.000 000 001
10⁻¹²	pico	p	Trillionth	Billionth	0.000 000 000 001
10⁻¹⁵	femto	f	Quadrillionth	Billiardth	0.000 000 000 000 001
10⁻¹⁸	atto	a	Quintillionth	Trillionth	0.000 000 000 000 000 001
10⁻²¹	zepto	z	Sextillionth	Trilliardth	0.000 000 000 000 000 000 001
10⁻²⁴	yocto	y	Septillionth	Quadrillionth	0.000 000 000 000 000 000 000 001

See also