The phrase “used synonymously” means that two or more words are employed in a way that they have the same meaning and can be interchanged in a particular context.
For example, the words “happy” and “glad” are often used synonymously. You could say “I am happy” or “I am glad” and the overall sentiment conveyed would be similar.
When words are used synonymously, it can add variety and richness to language. However, it’s important to note that even when words are considered synonyms, there may still be subtle differences in nuance or usage. Sometimes one word might be more appropriate in a specific situation than another, even though they have a similar general meaning.