The keyword term is a noun phrase. The head word, "theme," is a noun, which serves as the core part of speech. The proper noun "Patriot Day" functions as a noun adjunct, modifying "theme" by specifying its type or context.
A noun adjunct is a noun that modifies another noun, functioning similarly to an adjective. In this construction, "Patriot Day" provides specificity to the more general noun "theme." It answers the question, "What kind of theme?" The grammatical relationship is hierarchical, with "theme" being the primary element and "Patriot Day" being the subordinate, descriptive element. This structure is common in English, as seen in phrases like "computer screen" or "research paper," where the first noun defines the second.
For writing purposes, this entire noun phrase can be used in a sentence wherever a single noun is appropriate. It can act as the subject ("The Patriot Day theme resonated with the audience"), the direct object ("The organizers chose a new Patriot Day theme"), or the object of a preposition ("They created artwork based on the Patriot Day theme"). Understanding its function as a noun phrase is essential for constructing grammatically correct and clear sentences.
