Harmony refers to the "vertical" sounds of pitches in music, meaning pitches which are performed or sung alongside one another at the same time to create a chord. Generally, this means the notes are played simultaneously, Though harmony may also be implied by a melody that outlines a harmonic composition https://zpfeni.gov.bd/public/files/assets/ckeditor/kcfinder/upload/files/jenis-jenis-mp3-player.shtml