1. A book containing the words of a language, arranged alphabetically, with explanations of their meanings; a lexicon; a vocabulary; a wordbook. I applied myself to the perusal of our writers; and noting whatever might be of use to ascertain or illustrate any word or phrase, accumulated in time the materials of a dictionary. (Johnson)
2. Hence, a book containing the words belonging to any system or province of knowledge, arranged alphabetically; as, a dictionary of medicine or of botany; a biographical dictionary.
Origin: cf. F. Dictionnaire. See diction.