1. Asynchronous: Asynchronous operations in digital circuits are those that don't rely on a clock signal. Instead of being synchronized to a clock, asynchronous operations can occur independently of the clock signal.

2. Preset: Preset is a feature in digital circuits where the state of a flip-flop or a similar device is set to a predefined value when a preset signal is asserted. This is usually done asynchronously, meaning it can happen at any time, not necessarily synchronized with the clock.

3. Reset: Reset, on the other hand, is a feature that clears or initializes the state of a flip-flop or other digital element when a reset signal is asserted. Like preset, reset is often asynchronous.

So, "asynchronous preset and reset" together mean that the ability to set a specific state (preset) or clear the state (reset) of a digital element is not dependent on the clock signal and can happen at any time.