The term debouncing is also used in an analogous manner for electromechanical switches and is probably the origin of the term. These switches literally 'bounce'

The term debouncing is also used in an analogous manner for electromechanical switches and is probably the origin of the term. These switches literally 'bounce' off the contact during the first few milliseconds after the circuit is closed, rapidly opening and closing the circuit. Debouncing attempts to filter out these rapid, unwanted changes by e.g. adding a capacitor in parallel.