There is no usage guidance for this tag … yet!

Usage guidance, also known as a tag wiki excerpt, is a short blurb that describes when and why a tag should be used on this site specifically.

A phrase is a syntactic structure that consists of more than one word but lacks the subject-predicate organization of a clause. Except on a theory-specific basis for single-word, minimal instances of phrases. E.g. Any Noun, which is also a Noun Phrase.

Wikipedia definition