The keyword phrase "Lexington Patriots' Day celebration" functions as a noun phrase. The main point, or the head of the phrase, is the word "celebration," which is a noun. All preceding words act as modifiers describing this central noun.
In this grammatical construction, "celebration" is the core element that identifies the subject (an event). The words "Patriots' Day" form a compound noun that functions adjectivally to specify the type of celebration. Similarly, the proper noun "Lexington" acts as an adjectival modifier, further specifying which particular Patriots' Day celebration is being discussed. This layering of nouns serving as adjectives (noun adjuncts) is a common structure in English used to create specific and descriptive terms.
Therefore, when used in an article, the entire phrase "Lexington Patriots' Day celebration" should be treated as a single noun. It can serve as the subject of a sentence (e.g., "The Lexington Patriots' Day celebration draws large crowds."), the object of a verb (e.g., "We attended the Lexington Patriots' Day celebration."), or the object of a preposition (e.g., "Information about the Lexington Patriots' Day celebration is online.").
