Okay kiddo, let me tell you about gnossiennes! They are a type of music composed by a man named Erik Satie a long time ago.
You know how when you listen to some songs, they make you tap your foot or want to dance? Well, gnossiennes are different. They are slow and calming, and they don't make you want to dance or move around. They sound like beautiful piano pieces, played very softly and slowly.
Gnossiennes don't have any words, they are just instrumental music. That means a person plays them on a piano or other instrument without singing along. They can be very relaxing to listen to, kind of like when you go to bed at night and your parents play some soft music to help you fall asleep.
So, that's what gnossiennes are - beautiful and slow instrumental music that can help you relax and calm down.