What does "on the rocks" mean when serving a drink?

"On the rocks" refers to a drink that is served over ice, typically in a rocks glass. When a customer requests a drink "on the rocks," they are asking for the beverage to be poured directly over ice cubes, which helps chill the drink while slightly diluting it as the ice melts. This presentation enhances the drinking experience by keeping the beverage cold and ready to enjoy.

The choice of a rocks glass is also significant, as it is designed for short spirits or cocktails that are typically served in this manner, emphasizing both function and aesthetic appeal.