CHILD

• child plural children [countable]
• 1

  young person

  someone who is not yet an adult[= kid]:
• The hotel is ideal for families with young children.
• Your interest and support are important to your child.
• The film is not suitable for children under 12.
• I was very happy as a child (=when I was a child).
• three-year-old child/child of eight etc
• For a child of five this was a terrifying experience.
• parents with pre-school children (=children who are too young to go to school)
• an agreement to regulate child labour (=the use of children in industry)
• child killer/victim/prostitute etc (=a child who is a killer etc)
• the rights of the unborn child (=a baby that is still inside its mother)
• 2

  son/daughter

  a son or daughter of any age:
• I have five children, all happily married.
• She lives with her husband, Paul, and three grown-up children.
• Annie had always wanted to get married and have children.
• Alex is an only child (=he has no brothers or sisters).
• youngest/eldest child especially British English
• Our youngest child, Sam, has just started university.
• youngest/middle/oldest child especially American English
• 3

  somebody influenced by an idea

  someone who is very strongly influenced by the ideas and attitudes of a particular period of history
• child of
• a real child of the Sixties
• 4

  somebody who is like a child

  someone who behaves like a child and is not sensible or responsible - used to show disapproval:
• She's such a child!
• 5

   something is child's play

  used to say that something is very easy to do:
• I've cooked for 200 people before now. So, tonight is child's play by comparison.
• 6

   children should be seen and not heard

  an expression meaning that children should be quiet and not talk - used when you disapprove of the way a child is behaving
• 7

   be with child

  old use to be pregnant
• 8

   be heavy/great with child

  old use to be nearly ready to give birth

Definition from the Longman Dictionary of Contemporary English
Advanced Learner's Dictionary.