The core of the specified term is the proper noun "Patriots Day." The entire construction functions as a noun phrase, where the central noun is post-modified by an adjectival phrase that describes its nature.
A grammatical analysis deconstructs the term into two key components. The head of the phrase is "Patriots Day," a proper noun which names a specific entity (a film). The subsequent element, "based on true events," is a participial phrase. In this structure, the past participle "based" introduces a clause that functions adjectivally, modifying and providing essential information about the preceding noun.
Recognizing the term as a noun phrase is functionally significant for writing. It establishes the film itself as the article's primary subject. The modifier ("based on true events") then becomes the central thesis or attribute to be explored, guiding the article to focus on analyzing the film's relationship to the factual events it portrays. This ensures the subject remains the creative work, while its historical accuracy serves as the main point of discussion.