In music, dynamics refers to the volume or loudness of the sound or note, in particular to the range from soft (quiet) to loud. The term is also applied to the written or printed musical notation used to indicate dynamics.

The two basic dynamic indications in music are piano, meaning "softly" or "quietly", usually abbreviated as p; and forte, meaning "loudly" or "strong", usually abbreviated as f. More subtle degrees of loudness or softness are indicated by mp, standing for mezzo-piano, and meaning "half-quiet"; and mf, mezzo-forte, "half loud".

Beyond f and p, there is ff, standing for "fortissimo", and meaning "very loudly"; and pp, standing for "pianissimo", and meaning "very quietly". To indicate even more extreme degrees of intensity, more ps or fs are added as required. fff and ppp are found in sheet music quite frequently. Though these are simply more extreme degrees of "fortissimo" and "pianissimo," they are often referred to by the neologisms "fortississimo" and "pianississimo." More than three fs or ps is unusual, but Tchaikovsky indicated pppppp and ffff in passages of his Pathétique symphony.

In addition, there is sforzando, indicating a strong, sudden accent, abbreviated as sf or sfz; and fp (or sfp), which indicates sforzando followed immediately by piano. One particularly noteworthy use of this dynamic is in Joseph Haydn's Surprise Symphony. Rinforzando indicates that several notes, or a short phrase, are to be emphasized.

The Renaissance composer Giovanni Gabrieli was one of the first to indicate dynamics in music notation, but dynamics were used sparingly by composers until the late 18th century. Bach used the terms piano, più piano, and pianissimo (written out as words), and in some cases it may be that ppp was considered to mean pianissimo in this period.

In addition, there are words used to indicate gradual changes in volume. The two most common are crescendo, sometimes abbreviated to cresc, meaning "get gradually louder"; and decrescendo or diminuendo, sometimes abbreviated to decresc and dim respectively, meaning "get gradually softer". Signs called "hairpins" are also used to stand for these words. These are made up of two lines which connect at one end and get gradually further apart. If the lines are joined at the left, then the indication is to get louder; if they join at the right, the indication is to get softer. The following notation indicates music starting moderately loud, then becoming gradually louder and then gradually quieter:

Hairpins are usually written below the staff, but are sometimes found above, especially in music for singers. They tend to be used for dynamic changes over a relatively short period of time, while cresc and dim are generally used for dynamic changes over a longer range.

It should be noted that dynamic indications are relative, not absolute. mp does not indicate an exact level of volume, it merely indicates that music in a passage so marked should be a little louder than p and a little quieter than mf.

See also

• Musical terminology
• Accent (music)