Each term is assigned a five-digit number code used in searches. When appropriate, descriptors may include scope notes. Additional notations designate narrower, broader, and related terms. The 'USE' notation directs the user to the preferred descriptor for synonyms and near synonyms, while the 'USED FOR' notation shows the user that the descriptor includes the concept represented. Terms are listed alphbetically on a letter-by-letter basis. Additional sections contain organizational and geographical descriptors. A listing of key words out of context also in included. This edition has almost 40,000 descriptors.