Imprecision in meaning measured by inconsistency of indexing

Meaning is defined as the relevance of a word to the concept it labels. Following Hillman, meaning is tetradic: the relation of a word and a concept, to a degree, within a corpus, indexers, in choosing or assigning all words strongly associated with concepts of a document, assert that the document means the word; therefore, consistency of indexing measures the precision with which meaning is understood by the indexers. From an indexing experiment designed to avoid all judgments of truth or correctness of indexing, the following results were obtained: (1) When descriptors are freely chosen, the more descriptors assigned to a document, even when relatively few are assigned, the more difficult is the retrieval of it. (2) By restricting the descriptors used in searching, the disadvantage noted in (1) can be overcome. (3) Possibly, older words are used more frequently and less precisely than newer words. (4) A graph of the total number of applications of a descriptor versus the ranked document serial number lucidly illustrates the precision of meaning of the descriptor; a precisely understood word gives a rectangular curve; a less precise one, an S‐shape. Many words have imprecise meanings even to specialists in scientific fields.