Adiabatic rate is used to describe the change in temperature as a result of the rising or the sinking of an air parcel.
Knowing that the dry adiabatic rate of change for unsaturated air is 10°C/1000 m means that the temperature of the unsaturated air parcel would increase (get warmer) as the air parcel sinks and will decrease (get cooler) as the air parcel rises.
Hope this helps :)
