Terrain: H = Hilly, R = Rolling, F = Flat
Grouping:
Cruising speed is the typical speed maintained for uninterrupted flat distances with no wind.
Ride Average is what cycle computers calculate based on the total time the bike is moving.
Example: A ride listed as 35/C/F/S would be 35 miles, 11 to 13 mph cruising speed, flat terrain, and the group would all stay together.