The keyword phrase "september 11th on calendar" functions grammatically as a noun phrase. The core component, "September 11th," acts as a proper noun, which is the most crucial part of speech to establish as the main point for an article using this term.
A detailed grammatical analysis shows that "September 11th" is a proper noun because it names a specific, unique day. The subsequent prepositional phrase, "on calendar," acts as a post-modifier, providing context by specifying the location or medium where this date is noted. While "September 11th" can also function as an adjective when it modifies another noun (e.g., "the September 11th attacks"), the structure of the keyword phrase treats the date itself as the subject of interest. The entire phrase refers to a singular concept: the specific calendar entry for that day.
Therefore, for the purpose of developing an article, establishing "September 11th" as a noun is the correct analytical step. This classification allows the article to treat the date as a distinct entity, concept, or event in itself. It frames the topic around the day as the primary subject, rather than as a descriptor for something else, which is essential for maintaining a focused and coherent narrative.
