少子化 refers to the declining birth rate and shrinking population. It describes a situation where there are fewer children being born, leading to an aging society with a smaller workforce.
高齢化 (こうれいか): This term means "aging population" and is closely related to 少子化 since both involve demographic changes.
出生率 (しゅっせいりつ): This term refers to the birth rate, which is an important factor in understanding 少子化.
人口減少 (じんこうげんしょう): This term means "population decline" and encompasses both natural decrease due to low birth rates and net migration outflows.