Which reference material primarily provides synonyms and antonyms for words?

When you want to determine the part of speech of a word, which resource would you consult?

If you encounter an unfamiliar term in a science textbook, you might consult a:

To find the pronunciation of a word, which resource would be most helpful?

If you read a historical document and come across a word specific to that time period, which might you consult?

Which digital resource can help you find definitions, synonyms, antonyms, and example sentences?

You come across the word “ubiquitous” in a novel and want to understand its usage in different contexts. What should you consult?

For an in-depth understanding of a topic, including its historical and contextual background, you might consult a:

Which reference material provides brief definitions for terms as they are used in a specific text or field of study?

If you want to know the difference between the words “affect” and “effect,” which reference material should you check?