Learner's definition of CHILD
1 : a young person
— often used before another noun.
the birth of a child
She's pregnant with their first child.
a play for both children and adults
I went there once as a child. [=when I was a child]
a child prodigy
a child actor
3 : an adult who acts like a child : a childlike or childish person 4 : a person who has been strongly influenced by a certain place or time or by the events happening during that time
children should be seen and not heard
— used to say that children should be quiet and well-behaved