Demographic transition: Demographic transition refers to the process of shifting from high birth rates and death rates characteristic of pre-industrial societies to low birth rates and death rates typical of industrialized nations.
Dependency ratio: The dependency ratio is the measure of the number of dependents (children under 15 and adults aged 65+) relative to the working-age population (typically ages 15-64). A higher dependency ratio indicates a larger burden on the working-age population to support dependents.
Grey tsunami: Grey tsunami is a metaphorical term used to describe the impending wave of aging populations that will place significant pressure on healthcare, social systems, and economies.