To ignore repeats that arrive too fast to be meant. It waits for the trembling to settle before answering.
English de- (reversal) + bounce (Middle English bounsen, to knock, strike, likely imitative); to ignore repeats that arrive too fast to be meant, waiting for a signal's own trembling to settle before answering it.
The bounce it removes is a mechanical shudder, not a decision — a switch settling before it means what it says. Debouncing trusts stillness over speed: the first signal is not answered until it stops repeating itself.