A short solo used in jazz music or music with jazz influences. The fill is typically unwritten (ad lib) and is used as a background effect to add interest to passages in between phrases of the melody of the composition or when the melody is holding long notes. The fill is normally given to an instrument in rhythm section of the ensemble (bass, drum, guitar, or piano), but other instruments can provide melodic fills. In general, a fill is anything that is performed in addition to the written composition to "fill" a silence. It can also underscore a rhythm played by other instruments, announce the entrance or punctuate the exit of a soloist or other passages of the composition, stimulate the other performers to make the performance more interesting. The fill can either maintain the character of the composition or provide a contrasting character.
Characteristics of Fills