FORTISISSIMO

What happen if you want to play really loud, then you use 3 letters "fff" I have seen music that even have 4 or 5 letters "f" it all depend in the composer and how they want to perform their music. The symbol for very lod music is "fortisissimo"

When you see that symbol under the notes, you have to play those notes very loud. And you keep playing very loud until you see something different. So "fff" is louder than "ff"