Dynamic range is a measure of the sensor's ability to capture detail in extremely dark and bright areas. It's measured in EV (exposure values) and the higher the figure the better.
JPEG dynamic range analysis: Fuji cameras typically deliver lower dynamic range JPEGs than rival brands, presumably as a result of higher mid-tone contrast. This tendency is repeated here, though the X-Pro2 does at least deliver consistent results across its sensitivity range.
Raw (converted to TIFF) dynamic range analysis: The results are much closer when comparing raw files, and here there's little to choose between the X-Pro2 and the rest.