What is a defined area on a web page called where dragged items can be placed?

The correct term for a defined area on a web page where dragged items can be placed is "Drop Zone." This concept is integral to drag-and-drop functionality in web development, allowing users to interact with the interface in a more dynamic way. A drop zone typically changes visually to indicate to the user that it is ready to receive the dragged items, enhancing the user experience by providing clear feedback.

In contrast, other terms like "Client," "Cookie," and "Canvas" have specific meanings in web development that do not relate directly to this functionality. "Client" often refers to the user side of client-server architecture. "Cookie" pertains to a small piece of data stored on the user's computer by the web browser, which helps with session management and tracking preferences. "Canvas" refers to a HTML5 element used for drawing graphics on the fly via scripting, not specifically for the placement of draggable items. Thus, "Drop Zone" is the most accurate and relevant term among the provided options.