The first prefixes in physics were introduced in 1793—1795, when the metric system of measures was legalised in France. It was decided that the prefix names for multiples would be taken from Greek, and those for submultiples from Latin. The following prefixes were adopted in those years: kilo ... (from Gk. chilioi — thousand), hecto … (from Gk. hekaton — hundred), deca ... (from Gk. deka —ten), deci.. (from Lat. decem — ten), centi... (from Lat. centum — hundred), milli... (from Lat. mille — thousand).
In the following years the number of multiples and submultiples increased; the names of the prefixes for them were sometimes borrowed from other languages as well.
The following prefixes appeared: mega... (from Gk, megas — large), giga... (from Gk. gigas, gigantos — giant), tera... (from Gk. teras, teratos — huge, monster), micro... (from Gk. mikros — small, little), nano... (from Gk. nanos — dwarf), pico ... (from Ital. piccolo — small, tiny), femto... (from Dan. femten — fifteen), atto... (from Dan. atten — eighteen). The last two prefixes — peta... and exa... — were adopted in 1975: “peta”... (from Gk. peta — five, corresponding to five steps of 103), “exa” ... (from Gk. hex — six, corresponding to six steps of 103).
The table gives the decimal SI prefixes that denote an increase (multiples) or a decrease (submultiples) of units.
1 THz (1 terahertz) =1012 Hz (a trillion hertz)
1 MW (1 megawatt) = 106 W (a million watts)
1kV (1 kilovolt) = 103 V (a thousand volts)
1 μA (1 microampere) = 10-6 A (a millionth of an ampere)
1 pF (1 picofarad) = 10-12 F (a trillionth of a farad)
1 fs (1 femtosecond) = 10-15 s (a quadrillionth of a second)
In the following years the number of multiples and submultiples increased; the names of the prefixes for them were sometimes borrowed from other languages as well.
The following prefixes appeared: mega... (from Gk, megas — large), giga... (from Gk. gigas, gigantos — giant), tera... (from Gk. teras, teratos — huge, monster), micro... (from Gk. mikros — small, little), nano... (from Gk. nanos — dwarf), pico ... (from Ital. piccolo — small, tiny), femto... (from Dan. femten — fifteen), atto... (from Dan. atten — eighteen). The last two prefixes — peta... and exa... — were adopted in 1975: “peta”... (from Gk. peta — five, corresponding to five steps of 103), “exa” ... (from Gk. hex — six, corresponding to six steps of 103).
The table gives the decimal SI prefixes that denote an increase (multiples) or a decrease (submultiples) of units.
1 THz (1 terahertz) =1012 Hz (a trillion hertz)
1 MW (1 megawatt) = 106 W (a million watts)
1kV (1 kilovolt) = 103 V (a thousand volts)
1 μA (1 microampere) = 10-6 A (a millionth of an ampere)
1 pF (1 picofarad) = 10-12 F (a trillionth of a farad)
1 fs (1 femtosecond) = 10-15 s (a quadrillionth of a second)
| Prefix name | Prefix symbol | Multiplier | Multiplier name | |
|---|---|---|---|---|
| Russian | International | |||
| exa | Э | E | 1000000000000000000=1018 | quintillion |
| peta | П | P | 1000000000000000=1015 | quadrillion |
| tera | Т | T | 1000000000000=1012 | trillion |
| giga | Г | G | 1000000000=109 | billion |
| mega | М | M | 1000000=106 | million |
| kilo | к | k | 1000=103 | thousand |
| hecto | г | h | 100=102 | one hundred |
| deca | да | da | 10=101 | ten |
| deci | д | d | 0,1=10-1 | one tenth |
| centi | с | c | 0,01=10-2 | one hundredth |
| milli | м | m | 0,001=10-3 | one thousandth |
| micro | мк | μ | 0,000001=10-6 | one millionth |
| nano | н | n | 0,000000001=10-9 | one billionth |
| pico | п | p | 0,000000000001=10-12 | one trillionth |
| femto | ф | f | 0,000000000000001=10-15 | one quadrillionth |
| atto | а | a | 0,000000000000000001=10-18 | one quintillionth |