A dropdown menu is a common website navigation element that provides a list of options when clicked or hovered over. There are several synonyms for dropdown menu, including pull-down menu, drop menu, select menu, and cascading menu. Each of these terms describes a similar UI element used to provide a list of options for users to choose from. Some other related terms include pop-up menu, context menu, and flyout menu, each with its own specific functionality. Despite the subtle differences between these terms, they all refer to a type of interactive menu that is widely used in web design and software applications.