What is a wild card DNS?

Wildcards allow one record to stand in for a number of other records.
Wildcard is used in the name field of a record.
The "*" must be the only symbol in its label, and it must be the left most label.
example:
*.example.com IN A 192.168.0.1
fizz.example.com IN A 192.168.0.2
will match: www.example.com, foo.example.com
won't match: example.com or fizz.example.com