The core component of the phrase "patriots day based on" is the term "Patriots Day," which functions as a proper noun. This noun is the grammatical subject or head of the phrase, identifying a specific entity (either the 2016 film or the American holiday). The subsequent words, "based on," constitute a participial phrase that modifies this noun.
In a grammatical analysis, "Patriots Day" serves as the anchor of the expression. The phrase "based on" acts adjectivally, providing descriptive information about the noun. It is a reduced form of an adjective clause, such as "which is based on." For example, in the sentence, "The article discusses the film Patriots Day, based on the book Boston Strong," the phrase "based on the book Boston Strong" modifies "Patriots Day" by specifying its source material. The central element being discussed remains the proper noun.
Therefore, for the purpose of defining the main point or focus of the keyword term, the determining part of speech is a noun. The phrase "based on" is a subordinate, modifying element that adds context or specifies the foundation of that noun. Any article or analysis using this keyword would center on the entity named "Patriots Day," with its basis or origin being a secondary, explanatory detail.
