Throttle isn't right. It means reducing the rate of a repeated event into something more manageable, but the (reduced) repeat is still important and processed.
A debounce in electronics is taking the first signal when a mechanical switch is closed, and removing the subsequent ripple of current within a timeout (e.g. to remove the bounce of a keypress).
Usually, in the mechanical context, the signals in the ripple will be either high or low, so it doesn't really matter if you're taking the first, second, 21st or last: you're just smoothing out some unwanted static.
So what you want sounds to me like a debounce, except instead of taking a single signal in a given timeout (starting from the first signal), you want the final signal in another timeout (starting from the last-known signal).
You could call this something like final-signal debounce but I would probably avoid the word debounce. Perhaps something along the lines of final-signal processing, or a final-signal action or trigger. (Or last-signal....)