Question

what is a synonym? (required)
a word having the same or nearly the same meaning as another word
words that are closely related historically
words that describe one thing and one thing only

Explanation:

A synonym is defined as a word that has the same or nearly the same meaning as another word. The other options do not accurately describe synonyms. Historical - related words are etymologically - related, not synonyms. Words that describe one thing only are not synonyms.

Answer:

A. A word having the same or nearly the same meaning as another word