Triple Sec originated as a complementary product to Orange Curacao in the mid Nineteenth Century. The Combier distillery claims to have invented it in 1834. The name seems to have two meanings, "triple distilled" and "triple dry". Multiple distillations would yield a cleaner, clearer product which describes Triple Sec. Also, real Triple Sec is indeed drier than it's cousin Orange Curacao.
Both products originally used oranges grown on the Caribbean island of Curacao. Triple Sec is made with both bitter and sweet versions of these oranges on a neutral spirit base. Sugar was added to counteract the bitter orange and the resulting product was sweet but not overly so.
As time went by lower quality, sweeter versions started to enter the market (probably seeking to cash in on the popularity of Triple Sec). Eventually there were so many cheap knock offs flooding the market that we have gotten to the situation we are in today. That is, Triple Sec is almost universally regarded as a cheap, sweet orange cordial.
The low quality and cloying nature of modern Triple Sec has turned me off of the product. I used to stock Triple Sec in my bar but have since upgraded to Cointreau and other higher quality orange liqueurs. Little did I know that I was going back to the future. You see, Cointreau is one of the original Triple Sec products that first appeared in 1875. In fact "Triple Sec" used to be part of Cointreau's name. But all of the insipid competitors ruined the brand so Cointreau dropped the "Triple Sec" part of it's name and use's their own name for their brand.
Have you found a quality Triple Sec other than Cointreau? If so, let us know in the comments.