metric system
Yes.
Metrology
metric system
It is the SI system - the International Standard system) .
The International System for Weights and Measures, better know as the SI or metric system.
Yes.
No they are not.
Metrics is the European system of weights and measures.
The system of measurement based on the kilogram and the meter is the "metric system" also called the "International System of Units" or SI. This can also be called M.K.S System.
They originated from the Roman system of weights and measures
It is an international standard, and it is much easier to calculate with the metric system.
Lagrange did not invent the English System. He worked, with the French Commission for the reform of weights and measures on the International System of Weights and Measures. That is an International System and, although the majority of the world now uses it, the English cannot lay claim to it.