What is an octave in musical terms?

An octave in musical terms refers to the interval between one musical pitch and another pitch that has double its frequency. This relationship is fundamental in music because it creates a sense of similarity and cohesion between notes; for example, when you move from a "C" note to the "C" note that is an octave higher, the higher note vibrates at twice the frequency of the lower note. This doubling occurs in many musical systems and is crucial for understanding pitch relationships within scales and harmony.

While the distance between two notes with the same name captures part of the essence of an octave, it does not fully explain the frequency aspect that defines it. The span of twelve half steps describes a full octave but does not clarify the critical frequency relationship. Lastly, the interval of a fifth pertains to a different musical relationship entirely, which is smaller than an octave and is not relevant to this definition. Understanding these distinctions helps clarify why the interval described as double the frequency accurately captures the essence of what an octave is in music.