A
measurement
is a quantitative observation consisting of a number,
a unit and sometimes of a prefix.
The unit
for volumes is litre (l), for weighing gramm (g),
for a distance meter
(m), velocity kilometers per hour,...
These units are not
always suitable for a measurement.
(Why
should you say: My syringe has a volume of 0.001 l,
a drop of water weighs 0.05 g?)
So a syllable is placed
in front of the unit:
Prefix
is a syllable in front of a unit enlarging or diminshing this unit
[by
1000 (kilo-), by 1/10 (deci-), 1/100 (centi-),1/1000 (milli-), 1/1000.000
(micro-)
or 1/1000.000.000 (nano)].