Is Triple Sec and orange liqueur the same thing?
While both orange curaçao and triple sec are types of orange liqueurs, the two terms are not exactly interchangeable — at least by their generally accepted (yet loose and unregulated) definitions.
Grand Marnier can be used in the recipe as the triple sec or orange liqueur it calls for.
In this regard, Can you substitute Grand Marnier for Triple Sec?
For many recipes, you can also use a premium-quality triple sec (Cointreau is a favorite) or curaçao.