Expression & tempo
Dynamics
Dynamics are the markings that indicate volume, running from pianissimo (very soft) through mezzo-forte to fortissimo (very loud).
The standard ladder is pp, p, mp, mf, f, ff, with ppp and fff at the extremes. They are relative, not absolute: a forte in a solo passage and a forte in a full orchestral tutti are entirely different amounts of sound, and reading them literally rather than contextually is a common student error.
On a string instrument, dynamics are produced by three interacting variables, bow speed, bow pressure, and the contact point between bridge and fingerboard. Adding pressure alone produces a louder but uglier sound; a real crescendo usually combines more speed, more weight, and a contact point moving toward the bridge.
Related terms
Every term in this glossary is taught in context somewhere in Arco's curricula, on the staff, on the keyboard, and on your own fingerboard at the same time.