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.

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 normally.

Trill

A rapid alternation between an indicated note and the one above, usually indicated by the letter tr written above the staff. The trill is also known as the shake. See trill for more details.

Mordent

The mordent is thought of as a rapid single alternation between an indicated note, the note above (in the case of the upper mordent) or below (in the case of the lower or inverted mordent) the indicated note, and the indicated note again.

The upper mordent is indicated by a short squiggle; the lower mordent is the same with a short vertical line through it:

As with the trill, the exact speed with which the mordent is performed will vary according to the tempo of the piece, but at moderate tempi the above might be executed as follows:

Listen to a passage firstly played with lower mordents, then played without. (OGG)

It should be noted that in the Baroque period, a Mordant (the German equivalent of mordent) was what later came to be called an inverted mordent and what is now often called a lower mordent. In the 19th century, however, the name mordent was generally applied to what is now called the upper mordent. This confusion over the meaning of the unadorned word mordent is what has led to the modern terms upper and lower mordent being used rather than mordent and inverted mordent.

Although mordents are now thought of as just a single alternation between notes, in the Baroque period it appears that a Mordant may sometimes have been executed with more than one alternation between the indicated note and the note below, making it a sort of inverted trill.

Also, mordents of all sorts might typically, in some periods, begin with an extra unessential note (the lesser, added note), rather than with the principal note as shown in the examples here. The same applies to trills, which in Baroque and Classical times would standardly begin with the added, upper note. Practice, notation, and nomenclature vary widely for all of these ornaments, and this article as a whole addresses an approximate nineteenth-century standard.

A lower unessential note may or may not be chromatically raised (that is, with a natural, a sharp, or even a double sharp) to make it just one semitone lower than the principal note.

Turn

A short figure consisting of the note above the one indicated, the note itself, the note below the one indicated, and the note itself again. It is indicated by a mirrored S-shape lying on its side above the staff. An inverted turn (the note below the one indicated, the note itself, the note above it, and the note itself again) is usually indicated by putting a short vertical line through the normal turn sign, though sometimes the sign itself is turned upside down.

If the turn symbol is placed directly above a note, it is performed exactly as outlined above. If it is placed between two notes, however, the note before the symbol is played, then the turn, and then the following note. So the following turns:

might be executed like this:

The lower added note may or may not be chromatically raised (see mordent).

The exact speed at which the notes of a turn are played can vary, as can its rhythm. The question of how a turn is best executed is largely one of context, convention and taste.

Appoggiatura

From the Italian word appoggiare, "to lean"; (pronounced approximately /ap-podge-a-TOO-ra/). The appoggiatura is important melodically and often subtracts for itself half the time value of the note it precedes (though in triple time, for example, it might receive two thirds of the time). The added note (the unessential note) is one degree higher or lower than the principal note; and, if lower, it may or may not be chromatically raised (see mordent).

The appoggiatura is written as a note of smaller size, like the acciaccatura but without the oblique stroke:

This would be executed as follows:

Listen to a passage with two phrases ending in appoggiaturas, followed by these two phrases without them. (OGG)

Musicians' mnemonic: the appoggiatura is longer than the acciaccatura because it is podgy.

Acciaccatura

From the Italian word acciaccare, "to crush"; (pronounced approximately /at-tchak-ka-TOO-ra/). The acciaccatura is perhaps best thought of as a shorter, less melodically significant, variant of the appoggiatura, theoretically subtracting no time at all from the principal note. It is written as a smaller note (often a quaver, or eighth note), with an oblique stroke through the stem:

The exact interpretation of this will vary according to the tempo of the piece, but the following is possible:

Whether the note should be played before or on the beat is largely a question of taste and performance practice. Exceptionally, the acciaccatura may be notated in the bar preceding the note to which it is attached, showing it is to be played before the beat. (This guide to practice is unfortunately not available, of course, if the principal note does not fall at the beginning of the measure.) Some pianists play both the acciaccatura and the main note simultaneously, releasing the grace note immediately.