Weak slot and filler structures allow for quick retrieval of attribute values, easy description of relation properties, and embrace aspects of object-oriented programming. A slot is an attribute-value pair, and a filler is a value that a slot can take. Semantic nets represent concepts as nodes and relationships as labeled arcs, and the meaning of a concept comes from its relations to other concepts. Frames represent real-world entities as collections of attributes and values through a hierarchical class structure.