What is Wildcard SSL Certificate?
A SSL/TLS Wildcard certificate is a certificate with a wildcard character (*) in the domain name field. This allows the certificate to secure multiple sub-domain names pertaining to the same base domain.
Wildcard certificates are more expensive than standard SSL/TLS certificates because they are multi-domain certificates with the same registered root. This makes them simple to provision and administer, rather than using multiple certificates for every single domain and subdomain.