[fre.quen.cy] n, pl -cies (1600) 1: the fact or condition of occurring frequently
2. a: the number of times that a periodic function repeats the same sequence of values during a unit variation of the independent variable b: the number of individuals in a single class when objects are classified according to variations in a set of one or more specified attributes
3: the number of repetitions of a periodic process in a unit of time: as a: the number of complete alternations per second of an alternating current b: the number of complete oscillations per second of energy (as sound or electromagnetic radiation) in the form of waves