Meaning

noun French general who became emperor of the French (1769-1821)

noun a rectangular piece of pastry with thin flaky layers and filled with custard cream

noun a card game similar to whist; usually played for stakes

originBorrowed from French Napoléon (“a given name, usually in reference to Napoleon Bonaparte”). In reference to coins, via French napoléon (“(slang) a coin that originally had the appearance of Napoleon's face in the obverse”). In reference to guns and possibly cards, a reference to Napoleon III.

Etymology from Wiktionary, CC BY-SA 3.0