trill

A trill is a rapid alternation between a note and the note above it (usually a step above in the prevailing key). The effect adds brilliance, energy, and decoration to a melodic line. Trills are indicated by the abbreviation tr above the note, sometimes with a wavy line extending through the passage. In Baroque music, trills were an expected ornament even when not written out, and there was considerable debate about whether they should begin on the upper note or the main note. Modern practice generally begins on the main note. A good trill should be even, controlled, and at a speed appropriate to the tempo and style. Long trills often end with a turn (a brief figure that leads smoothly into the next note).