proper noun/ɛn/
Aisne is masculine in French.
Aisne (a department of Hauts-de-France, France); Aisne (a left tributary of the Oise, flowing through the departments of Meuse, Marne, Ardennes, Aisne and Oise, in northeastern France)
From the Roman name, Latin Acinum, Latinized from the Gaulish river Axona.