The word we're grasping for here is DENSITY ALTITUDE.
ISA conditions corrected at the rate of 30' per MB pressure change and 120' per degree of temperature.
At 3000' Density altitude the aircraft will perform the same wether it is because it is at 3000' AMSL in ISA, or at sea level at 990 MB (= 690') and ISA + 20.(=2400').