(Entry 1 of 4) 1 : a young person kids in high school especially : child a married couple with two kids —often used as a generalized reference to one especially younger or less experienced the kid on the pro golf tour you poor kid. 2a : a young goat.
“Kid” is actually not a native English word. It is an early borrowing from Old Norse “kið” (“young goat”), and its descendants can still be found in modern Scandinavian languages, e.g. “killing” (literally “kid-ling”) in Swedish (also meaning “young goat”).
Legally, the term child may refer to anyone below the age of majority or some other age limit. The United Nations Convention on the Rights of the Child defines child as "a human being below the age of 18 years unless under the law applicable to the child, majority is attained earlier".