The keyword term functions as a complex proper noun phrase. The core of the phrase is the proper noun "Celebrity Millennium," which identifies a specific entity. This noun is post-modified by the date, which acts as a specifier to pinpoint a singular, unique event associated with that entity.
Grammatically, the component "Celebrity Millennium" is a compound proper noun. The subsequent component, "September 11 2025," is a temporal modifier. While a date can function adverbially in a full sentence (e.g., "The ship sails on September 11, 2025"), within this condensed phrase structure, it functions adjectivally to qualify the noun. The entire string operates as a single conceptual unit, naming a specific occurrence, much like a title or a designated event name.
For the purpose of an article, this grammatical structure dictates that the main point must be treated as a singular subject. The content should not focus on the ship in general or the date in isolation, but on the specific event defined by their intersection: a particular sailing, itinerary, or incident. Understanding the phrase as a unique identifier is crucial for targeting content and ensuring the article directly addresses the specific event implied by the query.
