The keyword term "sep 11 nyt crossword" is a noun phrase. The main point or head of this phrase, which dictates its grammatical function, is the noun "crossword".
In this phrase, "crossword" serves as the core noun, identifying the primary subject. The preceding elements, "sep 11" and "nyt," function as adjectival modifiers that specify which particular crossword is being referenced. "Nyt" is a noun adjunct (an abbreviation for New York Times used as an adjective) indicating the publisher. "Sep 11" is a date that further specifies the exact edition of the puzzle. Together, they form a compound noun that refers to a single, distinct entity.
Determining that the keyword is a noun phrase is crucial because it establishes that the article's subject is a specific object or concept. The article's purpose will be to define, describe, analyze, or provide information about this particular puzzle. This grammatical classification frames the topic not as an action (verb) or a quality (adjective), but as a tangible thing to be examined.