A thesaurus can be a valuable reference tool in which to find new words so that writing does not become repetitive. However, be careful when using a thesaurus because while the basic denotation or meaning of a word might be the same or similar, its connotation or emotional impact may be quite different. Not all words found in a thesaurus entry are interchangeable with one another, and evaluation needs to be made as to whether a particular word fits the context of the sentence in which it is being used.