Does the wildcard secure the apex domain in a SSL certificate?

The functionality of a wildcard depends on the type of SSL certificate:

• In a single domain certificate, the wildcard in the common name secures the apex domain (also known as the naked or root domain) and all its subdomains at the same level where the wildcard is set. For example, a common name like *.example.com will secure example.com, www.example.com, and mail.example.com, but not www.third.example.com.
• In a multi-domain certificate (MDC), the wildcard in the common name or a SAN (Subject Alternative Name) secures all subdomains at the same level where the wildcard is set, but it does not secure the apex domain. For instance, *.example.com will secure www.example.com and mail.example.com, but not example.com or www.third.example.com.