In the baroque period, it was common for performers to improvise ornamentation on a given melodic line. A singer performing a da capo aria, for instance, would sing the melody relatively unornamented the first time, but decorate it with additional flourishes the second time. Improvised ornamentation continues to be part of the Irish musical tradition[1], particularly in sean nós singing but also throughout the wider tradition as performed by the best players.

Ornamentation may also be indicated by the composer. A number of standard ornaments (described below) are indicated with standard symbols in music notation, while other ornamentations may be appended to the staff in small notes, or simply written out normally. Frequently, a composer will have their own vocabulary of ornaments, which will be explained in a preface, much like a code. A grace note is a note written in smaller type, with or without a slash through it, to indicate that its note value does not count as part of the total time value of the measure. Alternatively, the term may refer more generally to any of the small notes used to mark some other ornament (see Appoggiatura, below), or in association with other some ornament’s indication (see Trill, below), regardless of the timing used in the execution.

In Spain, these ornaments were called “diferenzias”, and can be traced back to the early 16th century, when the first books with music for the guitar were produced.