Sustain

From AudioLexic

• Sustain is the third type of parameter you encounter in a envelope. It's abbreviated as "S" like in ADSR. Sustain is the level reached after attack and decay when you maintain a note on.

• Sustain is also the name of the footswitch which maintains the note when you release it on the keyboard. This function is similar to the right footswitch on a piano. Note that some companies like Korg use the name of Damper instead.