Carbon fiber roving is woven into fabric
Carbon fiber is composed of carbon atoms bonded together to form a long chain. The fibers are extremely stiff, strong, light. Carbon fiber strands are finer than a human hair. These strands are twisted together like yarn (called a tow) and woven into carbon fiber fabric.
Unidirectional carbon fabric has all the carbon fiber aligned in the same direction. Unidirectional reinforcement makes it possible to create incredibly strong, light components by precisely orienting the carbon fiber to provide maximum strength in the desired direction where it is needed most.
Bidirectional carbon fabric has carbon fiber woven at certain angles such as 90 degree or 45 degree. These are more flexible and have high torsional strength.