# Proper name or term of comma thousandths grouping notation

What is the proper name or terminology of notation for using a comma to separate and group thousandths of a number?

As in, formatting large numbers for readability:

comma delimited    real number
1,000           1000
10,000          10000
100,000         100000
1,000,000        1000000


How would you refer to this grouping of every third digit?

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