What do people mean when they ask for "A strong one"? I've never been onto a bar, but on TV and in films, there is often a scene when the main character is a little sullen, or stressed, and he goes into a bar, and asks for "a strong one". I think this means something with a high alcohol content, but what type of alcohol are they referring to? Whiskey? Gin, Beer? Vodka?
Generally this means the customer wants more liquor and less soda/mixer/ice/whatever than is called for in the recipe.