|Definition:|| quantity representing the quantities in a finite set or in an interval,|
- for n quantities , by the positive square root of the mean value of their squares:
- for a quantity x depending on a variable t, by the positive square root of the mean value of the square of the quantity taken over a given interval of the variable:
Note 1 to entry: The root-mean-square value of a periodic quantity is usually taken over an integration interval the range of which is the period multiplied by a natural number.
Note 2 to entry: The root-mean-square value of a quantity is denoted by adding the subscript q to the symbol of the quantity.
Note 3 to entry: The abbreviation RMS was formerly denoted as r.m.s. or rms, but these notations are now deprecated.