MILLI (SYMBOL M) IS A SI PREFIX IN THE SI SYSTEM OF UNITS DENOTING A FACTOR OF 10-3, OR 1/1,000. ADOPTED IN 1795, THE PREFIX COMES FROM THE LATIN MILLE, MEANING ONE THOUSAND (THE PLURAL IS MILIA). SI PREFIXES 10N PREFIX SYMBOL SHORT SCALE LONG SCALE DECIMAL EQUIVALENT 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 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 [EDIT] SEE ALSO SI