noun · adult males, specifically those counted for labor or taxation in historical contexts

古代官府常按家中的人丁多少来摊派劳役。

noun · male domestic servants or retainers in a household

这些年迈的人丁已在王府里伺候了几十年。

the number of people in a family or general population

这家子人丁兴旺，子孙满堂。