About
A file / directory is located by its path.
The base name is the last part of the path (ie the file name and its extension if any)
With the copy and move file operation, the basename does not change by default (ie if not specified).
Example
The basename for the the below path:
/dir1/dir2/name.extension
is
name.extension
Utility
The basename core utility returns the base name
basename /mydir/mysubdir/basename
would return basename