A dictionary is a source you can use to find definitions of words.
A thesaurus is a source you can use to find synonyms/antonyms for certain words.
These two combined can help you choose words that are not commonly used and it can improve your vocabulary range. I personally use a thesaurus way more than a dictionary to find synonyms for common words such as “good” or “smart”
The answers honestly vary but I'll say.
Temperature (degree of heat and cold)
Winds (their movement and direction)
Rainfall (its causes and its seasons).
