The keyword term "Patriots Day explosion" is a noun phrase. Its core component and principal part of speech is the noun "explosion." The proper noun "Patriots Day" functions as a noun adjunct, modifying the head noun.
In this grammatical structure, "Patriots Day" acts like an adjective to specify which particular "explosion" is the subject. This formation, where one noun modifies another, is common in English for creating specific and descriptive names for events, objects, or concepts. The entire phrase operates as a single lexical unit to identify a distinct historical event, not to describe an action (verb) or a quality (adjective).
Identifying the term as a noun phrase is crucial because it establishes the article's main point as a specific, identifiable event. This dictates that the content's focus will be on defining, describing, and analyzing this incidentincluding its context, causes, and effects. The grammatical classification ensures the subject is treated as a concrete entity, providing a stable foundation for a factual and analytical narrative.
