What is middle c c4?

Middle C or C4 is the pitch name for the musical note with a fundamental frequency of approximately 261.626 Hz. It is located in the middle of the piano keyboard and is usually the first note that beginner musicians learn to read and play. Middle C is also a reference point used to identify and locate other notes on the musical staff and is known as the fourth C key on the piano. In terms of scientific pitch notation, middle C is represented as C4, where C indicates the note's pitch class and 4 denotes the octave number, with each successive octave being assigned the next higher number.