Oversampling

Oversampling is processing audio at a multiple of the target sample rate (2×, 4×, 8×…), then filtering and downsampling back.

Raising the Nyquist frequency gives new high frequencies somewhere to go before they can cause aliasing. Converters use it so they only need a gentle analog anti-aliasing filter. Saturation and limiter plugins use it so the harmonics they add don't fold back.