A "pathname" is a string that specifies the location of a file or directory in a file system. It provides a way to navigate through the hierarchy of folders and files, allowing users and programs to access specific data. Pathnames can be absolute, starting from the root directory, or relative, based on the current working directory. In computing, pathnames are essential for file management and organization. They often include the names of directories and subdirectories, separated by slashes (/) or backslashes (\), depending on the operating system. Understanding pathnames is crucial for tasks involving file manipulation and programming in languages like Python or Java.