Thank you for the answer. I encountered those terms for the first time, and could not find any information on the internet. I could explain 'field resolution' as equal to the common term 'resolution'.
I put numbers into the formula You wrote, and got an adequate result: range of sensor is + / - 8 G (8 000 mG), ADC is 16 bit, so digital resolution = 8000 / (2^16) = 0.12 mG.