What does the sample rate and sample size of audio means?

Here is a great article on all three terms you're asking about. To summarize, here are the three definitions:

1. bitrate: simply amount of data per second, this can vary within a file (variable bit rate) or have a static value
2. sample rate: a frequency of how many times audio is measured per second, usually measured in kilohertz (kHz); a usual number you might see is 44.1kHz. This is tied directly to bit depth or the number of bits measured in each cycle

So at this point, we have to do some math and see that bit rate is bits per second (usually measured in Mbits/seconds), so bit rate = sample rate x bit depth. As far as I know, your sample size would simply be one of these one-second chunks of data.

Doing the pure math will reveal that these files would be very large, however there are a number of compression algorithms employed to keep the files lower without losing significant quality.