diminuendo

A directive to a performer to smoothly decrease the volume of the specific passage of a composition. This can be designated with the word diminuendo at the beginning of the passage or with the "hair pin" symbol consisting of two horizontal lines that start apart at the left and come together to a point at the right. There is typically a dynamic mark at either end of the symbol indicating the desired volume before and after the diminuendo. This is often seen in its abbreviated forms dim. or dimi.