A catch-all email account is an address that is specified to receive all messages that are addressed to an incorrect email address for a domain. For example, you have three email addresses set up for coolexample.com; info@coolexample.com, sales@coolexample.com, and webmaster@coolexample.com, you can set up info@coolexample.com as a catch-all email account. Then, any email messages sent to manager@coolexample.com (or any other invalid email address), are sent to the catch-all account (info@coolexample.com).
You can set up one catch-all email account per domain name.