A cloth of woven carbon fiber filaments, a common element in composite materials

Composite materials are made from two or more basic material. They are not just placed together. They are merged together. This create a material with useful properties unlike the individual elements.

The composite material as a whole may behave differently from either of its parts. For example, reinforced concrete (made of concrete and steel) has resistance to pressure and to bending forces. Bullet-proof glass (made of glass and plastic) is far more resistant to impact than either glass or plastic on their own.