tuner
Definitions
An electronic device used to receive radio or television signals and convert them into audio or video output.
A person or device that adjusts a musical instrument to the correct pitch.
A component in a vehicle or machine that allows for the adjustment of performance or frequency settings.
Examples
The guitarist used a digital tuner to ensure every string was perfectly in pitch before the performance.
I adjusted the tuner on the old radio until I could clearly hear the local news station.