Sample rate is the how many samples per second the audio is measured in. Its the 44.1k 48k thing.
Imagine a squiggly audio waveform. If you zoom way in on it, you can see the smooth curves turn into little staircases.That’s the only way to digitize an analog signal. Each one of these steps is a sample. If you audio is 48k, there are 48,000 steps per second.
FCP will allow you to manipulate the audio down to the sample, so in a sense, audio is really 48,000 fps.
This has nothing to do with my question though 🙂