[] the changing number of births, deaths, diseases, etc. in a community over a period of time; the scientific study of these changes人口统计；人口统计学；人口学◆Demography is a useful starting point for looking at future economic developments.人口统计学是研究未来经济发展的有用的起点。the basic features of a particular population特定人口的基本特征◆The mobility and demography of the workforce is changing.劳动力的移动性及人口特征正在发生变化。