This is a matter of hot debate! The question is so complex that it deserves to be explored further... although one thing is for sure: as an orange liqueur with quality and production requirements, Cointreau is more than a triple-sec.
Why? Simply because a triple sec is a generic name used for any orange-flavored spirit, while an “orange liqueur,” like Cointreau, goes a step further: as an officially recognized spirit category, there is certain legal production that needs to be fulfilled and qualified requirements to be considered a liqueur.
By using Cointreau in your cocktails rather than just a triple sec, you add the guarantee of the exceptional richness of 40+ aromas, quality sweet and bitter orange peels from the world’s finest terroirs, and 170 years+ of know-how—all resulting in a perfectly balanced cocktail. Thanks to age-old expertise as a liquor distiller, unique organoleptic qualities, and the art of Cointreau (art of selection, art of harmony, and art of distillation), Cointreau is an orange liqueur in a league of its own.