# Trill (Italian: trillo)

Source: https://arcosounds.com/glossary/trill
Also known as: tr

**A trill is a rapid alternation between the written note and the note directly above it in the key, marked tr above the staff.**

On a string instrument the trill is made by one finger hammering the string while the finger below stays down. The lower note is the written pitch; the upper is a step above it in the prevailing key, which means a trill on the same written note is a semitone wide in one key and a whole tone wide in another. Reading the key signature before trilling is not optional.

How the trill starts and ends depends on period. Baroque and Classical practice often begins on the upper note and may add a turn at the end; nineteenth-century and later practice usually begins on the written note. Editions differ, and a good edition tells you what it has assumed.

The technical difficulty is evenness rather than speed. A trill practised slowly with a metronome, gradually accelerating, ends up faster than one practised fast from the start, because the latter trains a tremor rather than a controlled alternation.

Canonical source: https://arcosounds.com/glossary/trill