Wiktionary
n. (context meteorology English) The rate of change in atmospheric temperature with increase of height. The variable normally is temperature unless specified otherwise. This is a vertical direction of travel (up or down), and the temperature may rise or fall suddenly.
Wikipedia
The lapse rate is defined as the rate at which atmospheric temperature decreases with an increase in altitude. The terminology arises from the word lapse in the sense of a decrease or decline. While most often applied to Earth's troposphere, the concept can be extended to any gravitationally supported parcel of gas.
Usage examples of "lapse rate".
This served to adapt the speed or the time-lapse rate of his own thoughts to the alien real-time of the Solitude Intelligence.
If they knew that the clouds were condensed water, they could roughly calculate the temperature lapse rate of the atmosphere, because the temperature had to fall to about minus forty degrees Centigrade at the altitude of the highest clouds she could see.