What do the abbreviations on this Jeppesen Dataplan mean?
GRS = Groundspeed

MCS = Magnetic Course

FU = Fuel burned that leg (100s)

FR = Fuel Remaining

T = OAT in degrees C, apparently without the sign.

S = Shear value (measure of turbulence) forecast

FF/E = Fuel Flow per Engine per hour 

With thanks to @mins for filling in the gaps!