hertz
n. plural-onlyn. a unit used to measure how often something happens in one second. You usually see it when talking about sound waves, radio signals, or computer speeds.
n. the SI unit of frequency, equal to one cycle per second. Named after Heinrich Hertz, it is used to quantify periodic phenomena such as electromagnetic waves and acoustic vibrations.
Human hearing usually ranges from 20 to 20,000 hertz.
The technician adjusted the radio transmitter to broadcast at a specific frequency measured in hertz.
Modern computer processors operate at billions of cycles per second, meaning their clock speeds are typically measured in gigahertz rather than simple hertz.
From German Hertz.
The word remains 'hertz' in both singular and plural forms; it does not take an 's' at the end for pluralization.