| item under consideration defined according to function or effect|
Note 1 to entry: A functional unit produces the interactive effect between input variables and output variables.
Note 2 to entry: A functional unit may be implemented by one or several physical units or program modules.
Note 3 to entry: If compound terms are used to designate functional units, the following should be used as the last word (in ascending order of rank),
Note 4 to entry: This entry was numbered 351-32-02 in IEC 60050-351:2006.