Question

Which tool can be used to find synonyms for a word?

Dictionary

Thesaurus

Glossary

Atlas

Answer 1

the answer is Thesaurus. Stay lit, hope this helped.

Answer 2

Thesaurus is the tool where you can find synonyms for a word, and even antonyms. 
Although you can find synonyms in a regular dictionary as well, thesauri are better when it comes to that.