Key Difference: Dictionary is a collection of words which lists words and their meanings. On the other hand, thesaurus is a collection of words grouped on the basis of similarity in their meanings (synonyms).

A dictionary is a very important tool to learn or understand a language. It contains a list of words usually in alphabetic order. This listing of words contains the information of the meaning of that word also. It also provides details like orthography, pronunciation and importance of these words. A dictionary contains words in one or more specific languages. It is also known as wordbook, lexicon or vocabulary.

Thesaurus is also a type of dictionary which lists words but in a way that it represents groups of words having similar meaning. Its integration with word processing software has helped writers in many ways. A writer can choose a suitable word by looking at it. It avoids the situation where one has to repeat the same word many times. Thus, thesaurus can be described as a list of words and similar meanings (synonyms). It may also list antonyms sometimes.

In simple words, dictionary provides the meaning of a word. On the other hand, thesaurus provides the word with the same meaning. Both in the form of books, are frequently used as reference books.

Comparison between Dictionary and Thesaurus:

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