Have the definitions of time and metric meter changed over years?

i remember the French came up with metric meter by measuring the distance between equator and north pole and then divided by an integer to come up meter. it that still the defintion for meter?

also, it seems now that a second is defined by the integer number of oscillation of atomic clock instead of divided a day divided by 24 hours by 60 minutes by 60 seconds.

just want to get a clear idea how these basic units are defined in modern times.
very good, thanks!

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