Globbing refers to the expansion of shell metacharacters to complete file names. Shell globbing metacharacters are '*' and '?', which expands to a sequence of zero or more characters and exactly one character respectively.
You use globbing (what a funny word!) to expand a file specification into a list of matching files. For example, *.pl might be matched by test.pl and foo.pl. Use the glob() function to do your globbing.