The term 'Star Over Calais' is a reference to the World War I battle of the same name. The French town of Calais was the site of a major battle between the British and German forces in 1914. The British forces were led by General Sir John French, who was known as the 'Star Over Calais' due to his leadership during the battle. The crossword solution for this term is 'etoile', which is the French word for star.