The keyword term "boston explosion patriots day" functions grammatically as a compound noun or a noun phrase. The head noun, which is the main point of the phrase, is "explosion." The words "Boston" and "Patriots Day" are proper nouns that act as adjectival and adverbial modifiers, respectively, specifying the location and time of the event.
In this construction, "explosion" serves as the core concept. The proper noun "Boston" acts as an attributive noun, modifying "explosion" to specify its geographical location. The proper noun "Patriots Day" functions as an adverbial phrase of time, pinpointing when the event occurred. The combination of these nouns creates a highly specific reference, distinguishing it from any other explosion by tying it to a precise place and a particular holiday, which is when the Boston Marathon is held.
This grammatical structure is significant because it consolidates multiple pieces of information into a single, searchable unit. The phrase effectively becomes a proper name for a specific historical event: the terrorist bombing that occurred during the Boston Marathon on April 15, 2013. Its function as a cohesive noun phrase allows it to be used as a subject or object in a sentence and serves as an efficient label for archival, journalistic, and academic reference.
