A note is a sign used in music to represent the relative duration and pitch of sound. The word note is also used for the graphic representation of that pitch in a notation system (and sometimes its duration) or a specific instance of either.
The general and specific meanings are freely mixed by musicians, although they can be initially confusing: one can speak of "the second note of Happy Birthday to You" for example. The first two notes of Happy Birthday to You are the same note, meaning, "the first two sounds of Happy Birthday to You have the same pitch." A note is a discretization of musical or sound phenomena and thus facilitates musical analysis (Nattiez 1990, p.81n9).
Note name
A note with doubled frequency as another sounds very similar, and is commonly given the same name, called pitch class. The span of notes within this doubling is called an octave. The complete name of a note consists of its pitch class and the octave it lies in. The pitch class uses the first seven letters of the latin alphabet: A, B, C, D, E, F, and G (in order of rising pitch). The letter names repeat, so that the note above G is A (an octave higher than the first A) and the sequence continues indefinitely. Notes are used together as a musical scale or tone row.
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