1 [C,U] the number of people who live in a particular area, city or country (某地方的)人口,居民人数:
What is the population of your country?你们国家有多少人口?an increase/a fall in population人口的增加╱减少
2 [C] all the people who live in a particular place or all the people or animals of a particular type that live somewhere (居住在某地的)全部人或动物:
the local population当地居民the male/female population男性╱女性居民The prison population has increased in recent years.最近几年监狱犯人增加了。