acciaccatura
A very short grace note played as quickly as possible before the main note.
In Depth
The acciaccatura is written as a small note with a stroke through its stem, placed just before the main note. Unlike the appoggiatura, it has no measurable duration — the performer crushes it into the main note as quickly as possible, creating a brief, sharp dissonance.
This ornament adds bite and sparkle to a melodic line. It was widely used in Baroque keyboard music and remains common in classical piano repertoire. The word itself comes from the Italian acciaccare, meaning to crush, which perfectly describes the technique.
The word literally means a crushing in Italian — the ornament crushes into the main note so fast it barely registers as a separate pitch.