An only child is a child with no brothers or sisters. She was an only child, growing up an only child, the only child of the family.
The old belief that they turn out selfish and lonely has been tested repeatedly and does not hold — only children do as well as anybody on the measures that matter and slightly better on some. Families are smaller everywhere, so the pattern is now common.
1nounonly childA child with no brothers or sisters.
“As an only child, she often wished she had a brother or sister to play with.”
only child is a child.
Practised in Family & People, Babies & Growing Up