A scroll bar is a graphical user interface element that allows users to navigate through content that is too large to fit within a visible area. It typically appears on the side or bottom of a window and consists of a draggable slider, or thumb, that moves along a track. Users can click and drag the thumb to scroll through the content or click on the track to jump to a specific location. Scroll bars are commonly found in various applications, including web browsers, word processors, and image viewers. They help users access information efficiently without needing to resize the window. The functionality of scroll bars can vary across different operating systems, such as Windows and macOS, but their primary purpose remains the same.