Dynamics

Dynamics are the volume of music - usually shown by abbreviations from this range:

 pp - pianissimo - very soft
 p - piano - soft
 mp - mezzo piano - medium soft
 mf - mezzo forte - medium loud
 f - forte - loud
 ff - fortissimo - very loud

Volume change is shown:

 cresc - crescendo - gradually louder
 dim - diminuendo - gradually softer

There are a few more, less often seen:

 sfz - sforzando - 'forced' - with emphasis
 ppp - very very soft
 fff - very very loud
 fp - forte piano - loud, then immediately soft

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