fre·quen·cy 
(frēkwən-sē)
(frēkwən-sē)n. pl. fre·quen·cies
1. The property or condition of occurring at frequent intervals.
2. Mathematics & Physics The number of times a specified periodic phenomenon occurs within a specified interval, as:
a. The number of repetitions of a complete sequence of values of a periodic function per unit variation of an independent variable.
b. The number of complete cycles of a periodic process occurring per unit time.
c. The number of repetitions per unit time of a complete waveform, as of an electric current.
3. Statistics
a. The number of measurements or observations having a certain value or characteristic.
b. See relative frequency.
[Latin frequentia, multitude, from frequēns, frequent-, crowded, numerous, frequent.]