A number of computer-based text-search systems currently in operation permit the use of word fragments as search terms. The full potential of this feature is not realized because of the uncertainties associated with the use of word fragments. A pair of dictionaries is described which makes possible the selection of appropriate fragments both for “generic” retrieval and for retrieval of specific words. The general nature of the computer program used to produce the dictionaries is described. © 1969, American Chemical Society. All rights reserved.