Like a scale, an arpeggio is linear: it’s a set of notes that you play one at a time either in order or otherwise. Like a chord, it is made up of only certain notes from that set. So an arpeggio is a chord played like a scale.

Let’s say we have an A major chord. It is made up of A, C#, and E. Instead of playing them all at once like we would with a chord, we play them individually: A C# E A C# E A C# E A C#…

Here is a list of all of the major chords and their arpeggios, just so you can see how they all work. It is recommended that you play all of these on your instrument right now!

Most melodies don’t just use the previous or next note in a scale. There are some exceptions, such as Mary Had a Little Lamb. In the key of C:

E D C D E E E… Each note is right next to another one on the C scale.