Derived expression refers to a word or phrase that is created by deriving it from another word or phrase. Synonyms for this term include derived word, derivative, derived form, derived term, and secondary expression. They all imply the same meaning, which is something that is created from a primary source. Using a derived expression is often helpful in clarifying meaning or emphasizing a particular point. It can also be an effective way to make language more concise and more accurate. Whether you use the term "derived expression," "derived form," or any of its other synonyms, they all convey the same idea and are equally valid in their usage.