Harmony refers back to the "vertical" Seems of pitches in music, which suggests pitches that are played or sung with each other simultaneously to create a chord. Generally, this means the notes are performed simultaneously, Even though harmony might also be implied by a melody that outlines a harmonic composition https://centrenet.centre.edu/ICS/icsfs/how-to-choose-a-good-mp3-player-to-play-songs.html?target=d119108a-c893-4082-a982-42856e056c90