The word "child" can be used as a noun or an adjective in Engpsh.

As a noun, "child" refers to a young person who is not yet an adult. For example:

"I have two children." (This sentence uses "child" as a noun to refer to two young people.)

As an adjective, "child" can be used to describe something that is related to or intended for children. For example:

"We watched a child-friendly movie last night." (This sentence uses "child" as an adjective to describe a movie that is suitable for children.)

"The school has a child-sized playground." (This sentence uses "child" as an adjective to describe a playground that is designed for children.)

In both cases, the word "child" is used as a modifier to describe something else.