# 6.6: §128. The Metric System

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## §128. The Metric System

The METRIC SYSTEM was developed in France during the decade that followed the French Revolution (1790-1799); the terminology was all drawn from Greek or Latin. The SYSTÈME INTERNATIONAL (SI) is a 20th century refinement and extension of metric, formally approved in 1960; its terminology goes beyond Greek and Latin. An excellent summary can be found in the *Encyclopedia* *Britannica*.

Some original metric measures: | ||

length | METRE | (< G μετρον): originally defined as “one ten-millionth part of a meridional quadrant of the earth” (the quadrant of the earth’s circumference running from the North Pole through Paris to the equator) |

area | ARE | (< L area): 10 m x 10 m (= 100 m^{2})HECTARE (100 ares): 100 m x 100 m (= 10,000 m ^{2}) |

mass | GRAM | (< Late L gramma, “small weight” < G γραμμα): 1 cc of distilled water at maximum density (4°C), weighed in vacuo |

volume | LITRE | (< ML litra < G λιτρα, “a measure”): a cube 10 cm x 10 cm x 10 cm (1,000 cc); thus l litre of pure water has a mass of 1 kg |

STERE | (< G στερεος): 1 cubic metre, or a cube 100 cm x 100 cm; thus 1 stere is equivalent to 1 kilolitre. |

**Prefixes in SI Measurement:**

Multiple | Prefix | Symbol | Etymology | |||

trillion | 10^{12} | tera- | T | G | τερας | “monster” |

billion | 10^{9} | giga- | G | G | γιγας | “giant” |

million | 10^{6} | mega- | M | G | μεγας | “big” |

thousand | 10^{3} | kilo- | k | G | χιλιοι | |

hundred | 10^{2} | hecto- | h | G | ἑκατον | |

ten | 10 | deka- | da | G | δεκα |

Submultiple | Prefix | Symbol | Etymology | |||

tenth | 10^{-1} | deci- | d | L | decem | |

hundredth | 10^{-2} | centi- | c | L | centum | |

thousandth | 10^{-3} | milli- | m | L | mille | |

millionth | 10^{-6} | micro- | μ | G | μικρος | small |

billionth | 10^{-9} | nano- | n | G | νανος | dwarf |

trillionth | 10^{-12} | pico- | p | It. | piccolo (?) | small |

quadrillionth | 10^{-15} | femto- | f | Dan./Norw. | femten (15) | |

quintillionth | 10^{-18} | atto- | a | Dan./Norw. | atten (18) |