Storage and Retrieval of Aspects of Meaning in Directed Graph Structures An experimental system that uses LISP to make a conceptual dictionary is described. The dictionary associates with each English word the syntactic information, definitional material, and references to the contexts in which it has been used to define other words. Such relations as class inclusion, possession, and active or passive actions are used as definitional material. The resulting structure serves as a powerful vehicle for research on the logic of question answering. Examples of methods of inputting information and answering simple English questions are given. An important conclusion is that, although LISP and other list processing languages are ideally suited for producing complex associative structures, they are inadequate vehicles for language processing on any large scale-at east until they can use auxiliary memory as a continuous extension of core memory. CACM March, 1966 Simmons, R. F. CA660316 JB March 3, 1978 11:25 AM 1155 4 1456 1456 4 1456 1468 4 1456 1515 4 1456 1699 4 1456 1856 4 1456 2127 4 1456 1324 5 1456 1456 5 1456 1456 5 1456 1456 5 1456