The .desktop file fills two primary functions: first, it informs the desktop environment how the file is to be handled by the desktop environment with regard to menu placement, display, environmental variables, and similar. In this function, it resides globally in /usr/share/applications/ and for specific users in $HOME/.local/applications.

If you come from the world of Windows, you undoubtedly understand the concept of a shortcut. In the Linux world, shortcuts do exist, but they're generally referred to as symbolic links, or symlinks. They are so named because, like shortcuts, a symlink is really just a symbolic placeholder or link to the file or directory you're trying to get at.