"an incendiary," especially one of the adherents of the Commune who used petroleum to set fire to the public buildings of Paris upon the entry of the national troops, 1871, from French pétroleur, from petrole (see petrol). The fem. form is pétroleuse.
"soft, sweet paste made of melted chocolate and cream," 1962, from Italian, the thing itself is said by Ayto ["Diner's Dictionary"] to have been created in Paris c. 1850; the name is of unknown origin. It is attested 19c. as the name of a kind of garment and an insult ("blockhead").
decorative and architectural style popular from 1925-1940, the name attested from 1966, from shortening of French art décoratif, literally "decorative art" (see decorative); the French phrase is from the title of L'Exposition Internationale des Arts Décoratifs et Industriels Modernes, held in Paris in 1925.