Noun

1. The rate of occurrence of anything; the relationship between incidence and time period.
   • With growing confidence, the Viking’s raids increased in frequency.
   • The frequency of bus service has been improved from 15 to 12 minutes.
2. The property of occurring often rather than infrequently.
   • The FAQ addresses questions that come up with some frequency.
   • The frequency of the visits was what annoyed him.
3. The quotient of the number of times $n$ a periodic phenomenon occurs over the time $t$ in which it occurs: $f\; =\; n\; /\; t$.
   • The frequency of the musical note A above middle C is 440 oscillations per second.
   • The frequency of a wave is its velocity $v$ divided by its wavelength $\backslash lambda$: $f\; =\; v\; /\; \backslash lambda$.
   • Broadcasting live at a frequency of 98.3 megahertz, we’re your rock alternative!
   • The frequency for electric power in the Americas is generally 60 Hz rather than 50.