A thesaurus is a reference book used to find synonyms or words that mean the same. Words are listed in a thesaurus in alphabetical order. To help your child better understand the concept of using a thesaurus, encourage your child to look through one. After doing this, give your child a word to look up. Tell him/her to find three words that are synonyms for the word given. For example, you might have your child look up the word “big”. Your child might look up the word and find the synonyms; huge, humongous, and enormous.