Blocks are a collection of objects that act as one single object. These are useful as they allow repetitive items to be inserted into the drawing quickly and are smaller than copying items over and over. For example, a door or window block would save time and file space in the creation of a floor plan.

Blocks maybe created from scratch, but AutoCAD also has a library of standard blocks that can be used. Typically companies will create their own libraries to keep consistency across a business.