someone's child; human being
Refers to a person as a child of someone, or more broadly as a human being. Often used in a humble or philosophical context.
To parents, their child is always a child.
other people's children
Used when contrasting one's own children with those of others. Often appears in set phrases like 人の子の世話をする.
Looking after other people's children is a big responsibility.
As a human being, everyone makes mistakes.
The expression 'the Son of Man' appears often in the Bible.
Compound of 人 (hito, 'person') + の (no, possessive particle) + 子 (ko, 'child'). Literally 'a person's child'. The extended meaning 'human being' arises from the idea that all humans are children of someone.