A stands for Architecture, D for Design, and N symbolizes Nième, representing an infinite set with no upper bound. This concept originates from the École Polytechnique in France in 1834, where "n" is used as a variable in universal design names, often with the suffix "-ième."

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In mathematics, N typically denotes the set of natural numbers, which is a countable, infinite set with no upper limit. Non-zero natural numbers, or positive integers (1, 2, 3, 4, …), can be used for counting (e.g., "three" apples on the table) or for ordering (e.g., the "third" largest city in the country).