What reference source would you use to find the meaning of thesaurus?

You would use a dictionary to find the meaning of the word "thesaurus".

Here's why:

* Dictionaries define words: They are specifically designed to provide the meanings, pronunciations, and other information about words.

* Thesaurus is a word: It's a noun that refers to a book of synonyms and antonyms.

While a thesaurus itself might list the word "thesaurus" as a synonym for itself, a dictionary will provide a clear, concise definition of the word.