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mètre

The metre, symbol m, is the base unit of length in the International System of Units (SI). It is defined as the distance light travels in vacuum in 1/299,792,458 of a second, a definition that fixes the speed of light at exactly 299,792,458 metres per second. The metre is used worldwide as the standard measure of length in science, industry, and everyday life.

The term metre comes from the French metre, which derives from the Greek metron meaning measure. Historically,

The metre has several submultiples and multipliers, including the centimeter (1/100 of a metre) and the millimeter

the
unit
evolved
through
several
definitions:
in
1791
the
metric
system
defined
the
metre
as
one
ten-millionth
of
the
distance
from
the
equator
to
the
North
Pole
along
the
meridian;
in
1889,
the
international
prototype
metre
bar
made
of
platinum-iridium
was
adopted
as
the
reference;
in
1960
it
was
redefined
in
terms
of
the
wavelength
of
krypton-86
light;
in
1983
it
was
redefined
again
in
terms
of
the
speed
of
light
in
vacuum.
(1/1000).
It
is
also
part
of
larger
units
like
the
kilometer
(1000
metres).
The
metre
remains
the
primary
unit
for
measuring
length
in
most
fields,
from
science
to
engineering
to
everyday
measurements.