The Aachen Article is a term that may refer to one of two things in the context of a crossword puzzle:
Aachen Article as a crossword clue: In this case, "Aachen Article" would likely be a clue in a crossword puzzle, where the solver is expected to provide the answer, which is "DER" (in German), meaning "the" in English.
Aachen Article as a historical document: The term "Aachen Article" could also refer to a historical document. In this context, it would be referring to an agreement signed in 1748 between the Holy Roman Empire and France, which helped bring an end to the War of the Austrian Succession. However, this is unlikely to be the intended answer in a crossword puzzle, unless the puzzle specifically deals with history or politics.