The "metre" unit came first in history back in the 18th century. You can read more details on Wikipedia:
https://en.wikipedia.org/wiki/Metre
The exact definition has been adjusted over the years. It started as a measurement of a pendulum with a specific period, then was marked on a platinum-iridium bar based on a fraction of the circumference of the Earth. The current definition is based on the speed of light.
The centimetre is a variation of the metre based on SI prefixes. The modern form of the metric system was developed in 1960.
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