Roget's 21st Century Thesaurus enables users to learn and make sense of words in a way no other thesaurus does, with: 17,000 main words, alphabetically listed, with parts of speech and concise definitions, for convenient, at-a-glance decision making.450,000 synonyms, more than any other thesaurusA versatile, thorough compilation of words and phrases - from slang to common usage - to the most erudite of word choices.Hundreds of recently coined and common AmericanismsA unique Concept Index to find words with only one concept in mind, rather than a specific word. This process of linking words together mirrors the way we actually think. With its innovative Concept Index, this thesaurus enhances the traditional function of thesauri; the simple replacement of one word with another. The Concept Index enriches users' understanding of meaning and usage by grouping together main entry words that share a similar idea or property - achieving broad connections of language between such categories as: ACTIONS, CAUSES, LIFE FORMS, QUALITIES, SENSES, etc. The essential reference for the 21st century, this is the most up-to-the-minute thesaurus of American English today. students, professionals and general users will love its easy-to-use dictionary format and will find its reliable, accurate word choices indispensable.