Mordent
Fast alternation with the lower auxiliary note.
What it means
The mordent is a short ornament in which the main note alternates once quickly with its lower auxiliary note and returns immediately: main note, lower auxiliary note, main note. The figure is executed on the beat and takes only the beginning of its duration from the main note.
The name comes from mordere, “to bite,” and describes the effect: a short, sharp bite.
The most important distinction concerns the upper mordent, also called the inverted mordent, which executes the same fast alternation with the upper auxiliary note. The two figures are mirror images of each other and are notated with similar signs. The mordent differs from the turn in that only one neighbouring note is involved, and from the trill in that the alternation is not repeated.
A double mordent executes the alternation twice.
In the notation
The sign is a short zigzag line with a vertical stroke through it; that of the upper mordent is the same line without the stroke. An accidental below the sign indicates that the lower auxiliary note is altered. The signs stand above the note. In the French tradition the figure is called pincé and is notated there with its own signs.
Musical use
The mordent belongs to the fixed stock of ornaments in the Baroque and the Viennese Classical period. It accents individual notes, gives melodies sharpness, and often stands at the beginnings of motifs and on accented beats. On harpsichord and organ it also fulfils a tonal task, because it gives the note more presence.
In French music it is called pincé. In the nineteenth century the sign was often interpreted differently. It begins on the main note, goes to the lower auxiliary note, and returns quickly. The sign without the stroke, by contrast, usually designates the upper mordent.
Performance practice
Watch the accidentals: a small accidental at the sign changes the auxiliary note. Do not accent the auxiliary note. Check the sign carefully — the vertical stroke decides the direction. And with older music, determine from the preface which execution the edition recommends.