ELI5: Explain Like I'm 5

Octave

Octave is a music word that means "the distance between one note and another". It's like how a grown-up might take big or small steps when they walk - some steps are closer together and some are further apart. Octave is the same idea, but for notes!

When we play a musical instrument or sing a song, we make different notes by changing the frequency or speed at which we vibrate the sound waves. The higher the frequency, the higher the note. The lower the frequency, the lower the note.

An octave is the distance between two notes where the higher note has double the frequency of the lower note. For example, if you play a note with a frequency of 100Hz (let's call it note A), then the same note one octave higher (called note A an octave above) has a frequency of 200Hz - double the frequency.

People like to use the word octave because when you play two notes that are an octave apart, they sound very similar! In fact, they sound so similar that your ears might have trouble telling them apart. This is why musicians often use octave notes together to create a nice sounding melody or harmony.

To make things even more interesting, there are different types of octaves! Some musicians might talk about a "perfect" octave or a "diminished" octave, but these are more advanced concepts for later on.

For now, just remember that octave means the distance between two notes where the higher note has double the frequency of the lower note. And that two notes an octave apart sound very similar!