In music, the pitch of a note means how high or low the note is. In physics, it is measured in a unit called Hertz. A note that is vibrating at 261 Hz will be caused by sound waves that vibrate at 261 times a second. This will be Middle C on the piano.
Not all musical instruments make notes of a certain pitch. Many percussion instruments like drums, triangles and cymbals are instruments used for rhythms. They do not play tunes because they have no definite pitch (although often a definite pitch can just be heard when listening carefully.)
Some musicians have a sense of absolute pitch or perfect pitch. This means that they always know what note is being played, even without comparing it to another note. Having a sense of absolute pitch does not necessarily make someone a good musician, although it can be very useful.
- Pitch (music) Citizendium