noun
extreme population aging
Refers to a society where the proportion of elderly people is exceptionally high, often used in demographic or policy contexts.
日本は超高齢化社会に突入している。
Japan is entering a super-aged society.
高齢化 means 'population aging' in general, while 超高齢化 emphasizes an extreme or advanced stage of aging.
Compound of 超 (chō, 'super, ultra') + 高齢化 (kōreika, 'population aging').