Frames are records or object-like structures describing a given object. They consist of substructures called slots. Each slot represents a certain aspect of the object described by a frame. Slots could be divided into fasets which are just another sub-level of the description. Such a hierarchy is similar to data hierarchy in a human brain.
Frames are usually organized in some higher order relationships that specify how various frames interrelate. Frames also can be grouped using object oriented techniques, involving inheritance, to be more intuitive to develop.