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 renaissance composer Giovanni Gabrieli was one of the first to indicate dynamics in music notation. A dynamic accent is an accent created by 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 quasi-legitimate neologisms "fortississimo" and "pianississimo." More than three fs or ps is quite rare; as with the words for fff and ppp, musicians will sometimes facetiously add extra "-iss"es for each extra f or p.

There is some evidence that this use of an increasing number of letters to indicate greater extremes of volume stems from a convention dating from the 17th century where p stood for piano, pp stood for più piano (literally "more quietly") and, by extension, ppp indicated pianissimo. Antonio Vivaldi seems to have written using this convention, but it was largely replaced by the above, more familiar, system by the middle of the 18th century.

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. In other words, the further apart the lines, the louder the music. 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. 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.

There are also words to indicate sudden changes in volume. The most common of these is sforzando ("with force"), abbreviated to sfz, meaning "play the next note loudly". One particularly noteworthy use of this dynamic is in Joseph Haydn's Surprise Symphony.

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. Tchaikovsky indicated pppppp in a passage of his Symphony No. 6, but the music would probably not be played any quieter than p would in other pieces, or even in different parts of the same piece.

See also

• Musical terminology