An acciaccatura is a musical ornament that consists of a very short, grace note played just before a main note. It is typically notated with a small note that is crossed through, indicating that it should be played quickly and lightly. The purpose of an acciaccatura is to add expressiveness and embellishment to a melody, creating a more intricate sound. In Western classical music, acciaccaturas are often found in the works of composers like Johann Sebastian Bach and Wolfgang Amadeus Mozart. They are commonly used in various musical styles, including Baroque and Classical music, enhancing the emotional impact of a piece.