The phrase "11 sep attentat" functions as a proper noun. It is a compound noun phrase that names a specific, singular historical event: the terrorist attacks that occurred on September 11, 2001. The term "attentat" is a noun borrowed from languages such as French and German, where it translates to "attack," "assassination," or "assault."
Grammatically, the phrase is constructed with a modifier and a head noun. The component "11 sep" acts as an adjectival modifier, specifying the date of the event. The word "attentat" is the head noun, identifying the nature of the event as an attack. When combined, they form a single lexical unit that refers to a unique moment in history, which is the defining characteristic of a proper noun.
Identifying this phrase as a proper noun is critical for contextual analysis and information processing. It ensures the entire term is treated as a single entity, preventing natural language processing systems or search algorithms from misinterpreting its components as separate, unrelated words. This correct classification is essential for accurate tagging, indexing, and retrieving information specifically related to the September 11th attacks.
