The keyword term "patriot day song lyrics" functions as a noun phrase.
Within this compound phrase, "lyrics" serves as the head noun, which is the core subject of the phrase. The preceding words act as modifiers, specifying the type of lyrics being referenced. "Song" is a noun acting as an adjective modifying "lyrics" (e.g., "song lyrics" meaning the lyrics of a song). "Patriot Day" is a proper noun (a specific day of remembrance), functioning adjectivally to modify "song" (e.g., "Patriot Day song" meaning a song related to Patriot Day). Therefore, the entire construction "patriot day song lyrics" refers to the words of a song associated with Patriot Day.
As a noun phrase, "patriot day song lyrics" can serve as the subject or object within a sentence, or as the main topic for an article, as indicated by its use as a keyword term. Its classification as a noun phrase is fundamental for understanding its grammatical role and its specific meaning.
