Maraschino Liqueur is an Italian cherry-based sweet liqueur with a long history in fine European cooking and baking as well as a distinguished presence in the Classic Cocktail repertoire.
Maraschino is a key ingredient in the Aviation cocktail, among many others.
It is also a requirement in our annual Nesselrode Pudding, which was in fact the first mention I had of Maraschino many years ago. The esteemed Monsieur Escoffier was a fine chef and I am deeply grateful for the effort and skill he used in assembling the Escoffier Cookbook, but I wish he had mentioned Maraschino Liqueur in his recipe instead of simply "Maraschino-flavored whipped cream": it was two years before I realized that he didn't mean the juice from the Maraschino Cherry jar!
Marashino is another one of those liqueurs that you buy by the bottle and use by the teaspoon, so your investment goes a long way. As M. Escoffier suggested, it is good in whipped cream and other sweets. It is clear in color.
I have found Maraschino in the North End and at Julio's and other high-end liquor stores in Massachusetts. I think it is available at the larger New Hampshire State Liquor Stores.