n (weather) A marked decrease in air temperature with increasing altitude because the ground is warmer than the surrounding air. This condition usually occurs when skies are clear and between 1100 and 1600 hours, local time. Strong convection currents exist during lapse conditions. For chemical operations, the state is defined as unstable. This condition is normally considered the most unfavorable for the release of chemical agents. See lapse rate.
n (legal) A common-law rule that if the person to whom property is will#Verb|willed were to die before the testator, then the gift would be ineffective.