noun
hertz
HURTS/hɜːrts/
A unit of frequency equal to one cycle per second.
The waveform repeats once per second, showing a frequency of one hertz.

Etymology
Hertz commemorates the German physicist Heinrich Hertz. The name serves as a scientific unit label for one cycle per second rather than literally describing frequency.
In context
Hertz is the unit of frequency and it just means waves per second it's usually shortened to Hz
More examples
- A light flashing once per second flashes at one hertz.
- Household alternating current in the United States runs at 60 hertz.
- This monitor refreshes its display at 144 hertz.
Forms
hertz
kilohertz noun — A frequency unit equal to 1,000 hertz.
megahertz noun — A frequency unit equal to 1,000,000 hertz.