The keyword phrase "Patriots Day a holiday" functions grammatically as a noun phrase with an appositive. The core part of speech for the main point is noun.
The analysis begins with identifying "Patriots Day" as a proper noun, which names a specific entity. The subsequent phrase, "a holiday," is a common noun phrase that serves as an appositive. An appositive is a grammatical construction that renames or further identifies the noun it follows. In this case, "a holiday" directly renames and defines "Patriots Day," clarifying its nature. The entire construction acts as a single conceptual unit, a noun phrase, where the central idea is the identification and classification of the subject.
Therefore, for an article using this keyword, the main point is fundamentally about a specific entity (a noun) and its classification. The article's focus is established by this noun-appositive structure: the subject is "Patriots Day," and its defining characteristic is that it is a "holiday." The entire phrase operates as a subject, not an action (verb) or a description (adjective), making noun the crucial part of speech.
