Dictionary vs Thesaurus
Although both dictionary and thesaurus are used to learn the meanings of the words in a language, they differ in the manner they impart the knowledge of the meanings of the words of the language.
A thesaurus is more of an etymological dictionary to know the meanings of words. A dictionary is an etymological and a grammatical tool of imparting knowledge of the words of a language.
A dictionary contains extra information regarding gender and parts of speech. In addition to getting the knowledge of a particular word of a language you could be supplied with some extra information too such as the gender of the word, the kind of the parts of speech to which the word belongs and etymological derivation of the word.
In other words it can be said that a word for example ‘boy’ will have information regarding its gender and about the kind of parts of speech to which the word ‘boy’ belongs, namely, noun. It is a common noun for that matter. A dictionary for that matter throws some light on the origin of words too.
A thesaurus on the other hand gives ample information about the other words that have the same connotation as the word you are referring to. In other words it can be said that a thesaurus gives synonyms and antonyms as well. Synonyms are words having the same connotation whereas antonyms are words that give the opposite meaning to the word you are concerned about.
Most people in general and writers in particular make use of a thesaurus to nicety to find out synonyms and antonyms. A thesaurus normally does not throw much light on the origin of words. In the same way it does not normally have extra information about the etymology of the words. A thesaurus has a lot of information about the other forms of words such as nominal forms, adjectival forms and adverbial forms.
A Dictionary is a book that has a collection of words from a specific language, mostly in alphabetical order with the definition and the usage of those words. It also gives additional information about a specific word such as: etymologies, phonetics, pronunciations, gender and parts of speech.
A dictionary also can be found in more than one specific language, such as English to French Dictionary where it contains a collection words in one language with their equivalents in another.
A thesaurus is a reference source that contains a classified list of synonyms with the related antonyms.