A file that is normally not visible for the user, unless the user requires to show the hidden files. It is still accessible by name and path as any other file.
A file that is normally not visible for the user, unless the user requires to show the hidden files by turning a setting in file explorer or using additional switch with command line tools. It is still accessible by name and path as any other file.
Windows systems have a true hidden file attribute allowing to hide file having any name. Unix systems (like Linux) do not have such attribute and instead hides all files whose names start from dot (like .ssh). Unix command ls requires an -a switch to list such files and folders.
Hiding files may result more user friendly behavior but it is also a method to mask viruses and other exploits.
